*codon*

n. (Molecular biology) a sequence of three nucleotides in a genome or a DNA or messenger RNA molecule, which specifies the incorporation of one amino acid or is a stop signal, during the biosynthesis of proteins. Codons occur within the protein-coding segments of the DNA or RNA genome of living organisms. The amino acid sequence of proteins synthesized on ribosomes is thus determined by the sequence of the nucleotides in the genome. [ PJC ]

☞ Outside of coding regions, there is no direct correspondence of the nucleotide sequence with protein sequence, and certain signalling functions of nucleic acids are not specified by three-nucleotide codons. Certain types of polypeptide synthesized in living organisms are not synthesized on ribosomes, and the sequences of these polypeptides do not have a corresponding nucleotide sequence in the genome. [ PJC ]

a. [ Gr. fanero`s evident + kw`dwn a bell. ] (Zool.) Having an umbrella-shaped or bell-shaped body, with a wide, open cavity beneath; -- said of certain jellyfishes. [ 1913 Webster ]

n. (Zool.) One of the Phocodontia. [ 1913 Webster ]

‖n. pl. [ NL., fr. Gr. fw`kh a seal + 'odoy`s, 'odo`ntos, a tooth. ] (Zool.) A group of extinct carnivorous whales. Their teeth had compressed and serrated crowns. It includes Squalodon and allied genera. [ 1913 Webster ]

a. [ Gr. &unr_; a case + &unr_;, &unr_;, a tooth. ] 1. (Anat.) Having the teeth inserted in sockets in the alveoli of the jaws. [ 1913 Webster ]

2. (Paleon.) Of or pertaining to the thecodonts. [ 1913 Webster ]

n. (Paleon.) One of the Thecodontia. [ 1913 Webster ]