[ si-truh-leen ]
/ ˈsɪ trəˌlin /

noun Biochemistry.

an amino acid, NH2CONH(CH2)3CHNH2COOH, abundant in watermelons and an intermediate compound in the urea cycle.

Origin of citrulline

1930; < New Latin citrull(us) the watermelon genus (Medieval Latin citrul(l)us, citrolus, Latinization of South Italian citrulo, Tuscan citri(u)olo < Late Latin citrium watermelon (derivative of Latincitrus (see citrus); apparently in reference to the citroncolored fruit of some types of watermelon), with -uolo < Latin -eolus) + -ine2 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for citrulline


/ (ˈsɪtrəˌliːn) /


an amino acid that occurs in watermelons and is an intermediate in the formation of urea. Formula: NH 2 CONH(CH 2) 3 CHNH 2 COOH

Word Origin for citrulline

C20: from Medieval Latin citrullus a kind of watermelon, from Latin citron, referring to its colour
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for citrulline


[ sĭtrə-lēn′ ]


An amino acid produced as an intermediate in the conversion of ornithine to arginine during urea formation in the liver.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for citrulline


[ sĭtrə-lēn′ ]

An amino acid originally isolated from watermelon, occurring mostly in the liver as an intermediate in the conversion of ornithine to arginine during urea formation. Chemical formula: C6H13N3O3.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.