Medical Definition of stop codon
: a genetic codon in messenger RNA that signals the termination of protein synthesis during translation <Each codon stands for one of the 20 amino acids that make up proteins or for one of three stop codons that signal the end of a protein chain.—Tina Hesman, Science News, 3 June 2000>—called also ; compare start codon
Seen and Heard
What made you want to look up stop codon? Please tell us where you read or heard it (including the quote, if possible).