actin

noun ac·tin \ ˈak-tən \
Updated on: 15 Nov 2017

Definition of actin

:a cellular protein found especially in microfilaments (such as those comprising myofibrils) and active in muscular contraction, cellular movement, and maintenance of cell shape

Recent Examples of actin from the Web

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Origin and Etymology of actin

probably from 2act or act(ivate) + 1-in


actin-

combining form
variants: or actini- or actino-

Definition of actin-

1 :having a radiate form
  • actinolite
2 :actinic radiation (such as X-rays)
  • actinometer

Origin and Etymology of actin-

borrowed from Greek aktino-, from aktīn-, aktís "ray, beam, spoke of a wheel"
Note: The Greek word has traditionally been linked with Sanskrit aktú-, conjectured to mean "twilight," and with Germanic *uŋhtwōn- "last part of the night, dawn," whence Old English ūhte "twilight, daybreak," Old High German uohta "dawn," Old Norse ōtta "last part of the night," Gothic uhtwo "dawn," from Indo-European *n̥kwt-u-n-, a zero-grade derivative of *nokwt-/*nekwt- "night" (see 1night). Robert Beekes (Etymological Dictionary of Greek, Leiden, 2009) rejects this connection on the grounds that aktís "shows no trace of a labiovelar." In reference to actinic radiation, the formative actino- was probably first used by John herschel in actinometer (1833).


Medical Dictionary

actin

noun ac·tin \ ˈak-tən \

medical Definition of actin

:a protein found especially in microfilaments (as those comprising myofibrils) and active in muscular contraction, cellular movement, and maintenance of cell shape — see f-actin, g-actin

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