[ lak-tam ]
/ ˈlæk tæm /

noun Chemistry.

any of a group of cyclic amides characterized by the NHCO group, derived from aminocarboxylic acids by the intramolecular elimination of water from the amino and carboxylic groups.

Origin of lactam

First recorded in 1880–85; lact(one) + am(ide) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for lactam

/ (ˈlæktæm) /


chem any of a group of inner amides, derived from amino acids, having the characteristic group -CONH-

Word Origin for lactam

C20: from lact (one) + am (ide)
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

Medical definitions for lactam

[ lăktăm′ ]


An amide formed from amino carboxylic acids containing a keto group in a ring configuration, as seen in purines, pyrimidines, and antibiotics. It is tautomeric to lactim.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.