exon 1
/ek"son/ , n.
(in Britain) one of four yeomen of the guard who act as commanding officers in the absence of higher authority. Also called exempt .
[ 1645-55; earlier exant, for F exempt (sp. altered to show F pronunciation) ]
exon 2
/ek"son/ , n. Genetics.
any portion of an interrupted gene that is represented in the RNA product and is translated into protein. Cf. intron .
[ 1975-80; ex ( pressed sequence ) + -ON 1 ]