Exon

An exon is any region of DNA within a gene that is transcribed to the final messenger RNA (mRNA) molecule, rather than being spliced out from the transcribed RNA molecule. Exons of many eukaryotic genes interleave with segments of non-coding DNA (introns). The term exon was coined by American biochemist Walter Gilbert in 1978: Function In many genes, each exon contains part of the open reading frame (ORF) that codes for a specific portion of the complete protein. However, the term exon is often misused to refer only to coding sequences for the final protein. This is incorrect, since many noncoding exons are known in human genes (Zhang 1998).
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Exon /ex·on/ the coding region in a gene. ex·on n. A nucleotide sequence in DNA that carries the code for the final mRNA molecule and thus defines a [more]Exon - Community and Resources

Noun
1. sequence of a gene's DNA that transcribes into protein structures; "exons are interspersed with introns"
(synonym) coding DNA
(antonym) intron
(hypernym) deoxyribonucleic acid, desoxyribonucleic acid, DNA

(n.)
An officer of the Yeomen of the Guard; an Exempt.
  

(n.)
A native or inhabitant of Exeter, in England.
  

A region of DNA in a gene that is transcribed ("read") into mature messenger RNA. An exon is the protein-coding part of a gene. As opposed to an intron.