Lipid

Definition: Lipid

Lipid

Noun

1. Any oily organic compound insoluble in water but soluble in organic solvents; essential structural component of living cells (along with proteins and carbohydrates).

Specialty Definitions: Lipid

Domain	Definitions
Health	Fat. (references)
Medicine	Total lipids including phospholipids. Source: European Union. (references)
Source: compiled by the editor from various references; see credits.

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Specialty Definition: Lipid

(From Wikipedia, the free Encyclopedia)

Lipids are fatty acid esters, a class of water-insoluble organic molecules, that are used as basic building blocks of biological membranes, as well as for energy storage (e.g., triglycerides). Lipids consist of a polar or hydrophilic (attracted to water) head and one to three nonpolar or hydrophobic (repelled by water) tails (Fig. 1). Since lipids have both functions, they are called amphiphilic. The hydrophobic tail consists of one or two (in triglycerides, three) fatty acids. These are unbranched chains of carbon atoms (with the correct number of H atoms), which are connected by single bonds alone (saturated fatty acids) or by both single and double bonds (unsaturated fatty acids). The chains are usually 14-24 carbon groups long.

Figure 1: Basic lipid structure. A lipid consists of a polar head group (P) and a nonpolar tail (U for unpolar). The lipid shown is a phospholipid (two tails). The image on the left is a zoomed version of the more schematic image on the right, which will be used from now on to represent lipids with one, two, or three chains.

For lipids present in biological membranes, the hydrophilic head is from one of three groups:

Glycolipids, whose heads contain an oligosaccharide with 1-15 saccharide (sugar) residues.
Phospholipids, whose heads contain a positively charged group that is linked to the tail by a negatively charged phosphate group.
Sterols, whose heads contain a planar steroid ring, for example, cholesterol (only in animals).

In an aqueous environment, the heads of lipids are turned towards the environment, and the tails are turned towards a hydrophobic region of another molecule. With lots of lipids present, the tails "prefer" to turn toward each other, forming a hydrophobic region. This can be a bilayer or a micelle (Fig. 2). Micelles are spheres and can only reach a certain size, whereas bilayers have no limit to their extension. They can also form tubules.

Figure 2: Self-organization of lipids.
Driven by hydrophilic and hydrophobic forces, the nonpolar tails of lipids (U) tend to cluster together, forming a lipid bilayer (1) or a micelle (2). The polar heads (P) face the aqueous environment.

Lipid bilayers form the foundation of all biological membranes.

Synonyms: Lipid

Synonyms: lipide (n), lipoid (n). (additional references)

Synonym by domain: fattest (medicine).

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Crosswords: Lipid

English words defined with "lipid": cholesterosis cutis ♦ fatty acid ♦ Gaucher's disease ♦ infantile amaurotic idiocy ♦ juvenile amaurotic idiocy ♦ lipid granulomatosis, lipidosis, lipoid granulomatosis, lipoprotein ♦ Niemann-Pick disease ♦ Sachs disease, Spielmeyer-Vogt disease ♦ Tay-Sachs, Tay-Sachs disease ♦ virion ♦ xanthoma multiplex, xanthomatosis. (references)

Specialty definitions using "lipid": 1,2-Dipalmitoylphosphatidylcholine ♦ 2-Keto-3-desoxy-octon acid ♦ 3-desoxy-D-manno-2 octulosonic acid ♦ 5,8,11,14,17-Eicosapentaenoic Acid ♦ Annexin I, Apolipoproteins ♦ BRL 26830A, Bromotrichloromethane ♦ Central fat distribution, Ceroid, Cholesterol Ester Storage Disease, Complement Membrane Attack Complex ♦ DepoFoam-encapsulated cytarabine, Dihydroxyacetone Phosphate, Dimyristoylphosphatidylcholine, Diphenylhexatriene ♦ Enterosorption ♦ Fatty Acids, Omega-3 ♦ Glucose Clamp Technique ♦ Histiocytosis, Non-Langerhans-Cell, Hyperlipidemia, Familial Combined, hypernephroma ♦ Ionophores, isoprenoid lipid ♦ Kdo, keto ♦ Lipid A, Lipid Bilayers, Lipid Mobilization, Lipid Peroxidation, Lipid Peroxides, lipid pneumonia, Lipid Solubility, Lipids and Antilipemic Agents, Lipofuscin, lipopolysaccharide, Lipopolysaccharides, liposome ♦ Membrane Fluidity ♦ Orlistat, Oxidative Stress ♦ Phytanic Acid, Pneumonia, Lipid, Pulmonary Surfactants ♦ renal-cell carcinoma ♦ Thiobarbituric Acid Reactive Substances ♦ Viral Matrix Proteins ♦ Wolman Disease ♦ Zona Reticularis. (references)

Non-English Usage: "Lipid" is also a word in the following languages with English translations in parentheses.

Danish (fat, lipid), German (lipid).

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Commercial Usage: Lipid

Domain	Title
Books	Arachidonate Related Lipid Mediators (Methods in Enzymology, Vol 187) (reference) Contemporary Diagnosis and Management of Lipid Disorders (reference) Disorders of Lipid Metabolism (reference) Enzymes in Lipid Modification (reference) Lipid Analysis (Introduction to Biotechniques) (reference) (more book examples)

Periodicals	Prostaglandins And Other Lipid Mediators (reference) (more periodical examples)
Source: compiled by the editor from various references; see credits.

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Photo Album: Lipid

Thumbnail	Description & Credit	Thumbnail	Description & Credit
	Biological laboratory technician Elizabeth Denvir extracts samples for total lipid and fatty acid composition. P.Credit: USDA ARS News; photo by Scott Bauer..		At large osmotic pressure long DNA fragments create a hexagonally ordered macromolecular array. Except for the symmetry of the subphase this experiment is equivalent to the multilamellar lipid subphase.Credit: NICHD.
	[Group portrait of lipid researchers at a meeting].Credit: National Library of Medicine.
Source: compiled by the editor from various references; see credits.

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Non-Fiction Usage: Lipid

Subject	Topic	Quote
Health		All are enveloped in a lipid (fat) membrane. (references)
		It is also an important regulator of protein and lipid metabolism. (references)
		The measurement of a single fasting triglyceride may inadequately represent this lipid. (references)
Source: compiled by the editor from ICON Group International, Inc.; see credits.

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Usage Frequency: Lipid

"Lipid" is generally used as an adjective (general or positive) -- approximately 97.73% of the time. "Lipid" is used about 264 times out of a sample of 100 million words spoken or written in English. Its rank is based on over 700,000 words used in the English language. Some parts-of-speech are not covered due to the samples used by the British National Corpus. (note: percents less than one-hundredth of one percent have been omitted)

Parts of Speech	Percent	Usage per 100 Million Words	Rank in English
Adjective (general or positive)	97.73%	258	18,412
Noun (proper)	2.27%	6	143,867
Total	100.00%	264	N/A

Source: compiled by the editor from several corpora; see credits.

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Expression: Lipid

Expressions using "lipid": isoprenoid lipid ♦ lipid A ♦ Lipid Bilayers ♦ lipid granulomatosis ♦ Lipid Mobilization ♦ lipid peroxidation ♦ Lipid Peroxides ♦ lipid pneumonia. Additional references.
Hyphenated Usage
	Beginning with "lipid": lipid-coated, lipid-containing, lipid-induced, lipid-laden, lipid-lowering, lipid-lowering medication, lipid-lowering medicine, lipid-metabolizing, lipid-storing, lipid-water.
	Ending with "lipid": protein-lipid.
Source: compiled by the editor from various references; see credits.

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Frequency of Internet Keywords: Lipid

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Expression	Frequency per Day	Expression	Frequency per Day
lipid	106	cornea deposit lipid retina	4
lipid profile	64	fasting lipid profile	4
lipid panel	63	lipid malondialdehyde peroxidation	4
lipid peroxidation	20	lipid lowering drug	3
lipid metabolism	15	lipid science	3
lipid malondialdehyde oxidative peroxidation stress	13	level lipid	3
lipid disorder	13	lipid panel result	3
lipid test	10	lipid synthesis	3
lipid lowering agent	10	lipid structure	3
journal lipid research	9	abdominal abdominal adipose adipose fat fat lipid lipoprotein replace testosterone visceral visceral	3
lipid rafts	7	lipid management	3
clinic lipid	6	lipid panel test	3
extraction lipid	6	lipid raft	3
bilayer lipid	6	fasting lipid panel	3
guggul lipid	6	blood lipid	3
lipid blood test	5	lipid study	3
lipid control	5	hagridden lipid	2
lipid testing	4	diet lipid	2
lipid lowering	4	behavioral effect intervention lipid long nursing regulation term	2
bilayer lipid membrane	4	health lipid	2
		lipid removal	2
Source: compiled by the editor from various references; see credits.

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Modern Translations: Lipid

Language		Translations for "lipid"; alternative meanings/domain in parentheses.
Arabic		‏دهن (butter, fat, grease, oil, paint, plaster, render, rub in, shortening, smear). (various references)

Danish		lipid (fat). (various references)

Dutch		lipide (fat). (various references)

Finnish		rasva (fat, grease, lubricating grease). (various references)

French		lipides, lipide. (various references)

German		Lipid (fat). (various references)

Greek		πνευμονία εξ εισροφήσεως ελαίου εντός των πνευμόνων (fat pneumonia, lipid pneumonia, lipoid pneumonia, oil aspiration pneumonia, pneumonolipoidosis), λιπιδικός έλεγχος (lipid determination), διαλυτά σε λιπίδια προφάρμακα μυτομυκίνης (lipid-soluble prodrugs of Mytomycin). (various references)

Italian		lipide (fat). (various references)

Japanese Kanji		脂質 (adipose, fats). (various references)

Japanese Katakana		ししつ (adipose, disposition, fats, nature, paper quality, private room, quality of teeth). (various references)

Korean		지질 (Geologic, Geological). (various references)

Pig Latin		ipidlay

Portuguese		lípido (fat), lípido. (various references)

Spanish		lípido (fat). (various references)

Swedish		lipid (fat). (various references)
Source: compiled by the editor from various translation references.

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Ancestral Language Translations: Lipid

Language	Period	Translations
Greek	700 BCE-300 CE	lipos. (various references)
Source: compiled by the editor from various references.

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Derivations & Misspellings: Lipid

Derivations
	Words beginning with "lipid": lipide, lipides, lipidic, lipids. (additional references)
	Words ending with "lipid": glycolipid, phospholipid. (additional references)
	Words containing "lipid": glycolipids, hyperlipidemia, hyperlipidemias, phospholipids. (additional references)
Misspellings
	"Lipid" is suggested in spellcheckers for the following: aipim, Alipio, Alipui, ipid, lapad, lapi, lapid, lapir, leipoa, libid, lific, liiad, liid, Limid, lipar, liped, lipet, Lipex, lipi, lipido, lipif, lipin, lipip, lipit, lipix, lipo, Lipsitz, Lipu, lirid, Llipi, lophii, lopid, lupid, Lupio. (additional references)
Source: compiled by the editor, based on several corpora (additional references).

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Rhyming with "Lipid"

# of Phoneme Matches	Pronunciation	Word(s) rhyming with "lipid" (pronounced lī"pud)
3	-p u d	bicuspid, Cupid, intrepid, rapid, stupid, tepid, torpid, tricuspid, vapid.
Source: compiled by the editor (additional references); see credits.

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Anagrams: Lipid

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "d-i-i-l-p"
	-1 letter: pili.
	-2 letters: dip, lid, lip.
	-3 letters: id, li, pi.
	Words containing the letters "d-i-i-l-p"
	+1 letter: limpid, lipide, lipids, lipoid.
	+2 letters: diploic, diploid, implied, lipides, lipidic, lipoids.
	+3 letters: dimplier, dimpling, diplegia, diploids, diploidy, diplopia, diplopic, diplosis, disciple, filliped, lapidify, lapidist, limpidly, lipoidal, milliped, peridial, pickadil, piddling, pindling, ploidies, pulicide, pygidial, sideslip, triploid, vilipend.
	+4 letters: acidophil, amplified, dimpliest, diplegias, diplontic, diplopias, discipled, disciples, duplicity, ellipsoid, guildship, imperiled, imploding, inclipped, insipidly, lapidists, limpidity, millipede, millipeds, pickadils, pigtailed, pilloried, pipelined, pixilated, placidity, presidial, pulicides, pycnidial, sideslips, spindlier, spindling, triploids, triploidy, vilipends.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.