noun An officer of the King's Body Guard of the Yeomen of the Guard.
noun A region of a transcribed gene present in the final functional RNA molecule.
noun ↑ "The notion of the cistron [i.e., gene] ... must be replaced by that of a transcription unit containing regions which will be lost from the mature messenger – which I suggest we call introns (for intragenic regions) – alternating with regions which will be expressed – exons." (Walter Gilbert 1978)