A section of DNA which carries the coding sequence for a protein or part of it. Exons are separated by intervening, non-coding sequences (cf. intron). In eukaryotes most genes consist of a number of exons.
PAC, 1992, 64, 143. 'Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)' on page 153 (https://doi.org/10.1351/pac199264010143)