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lactam

American  
[lak-tam] / ˈlæk tæm /

noun

Chemistry.

  1. 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.

lactam British  
/ ˈlæktæm /

noun

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

"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

Etymology

Origin of lactam

First recorded in 1880–85; lact(one) + am(ide)

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

As has been mentioned, chlorophyll a differs from chlorophyll b by having one more oxygen and two less hydrogen atoms in the molecule, and in having one of its nitrogen atoms in the "lactam" arrangement.

From The Chemistry of Plant Life by Thatcher, Roscoe Wilfred

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.