1) Azygos 2) Impar 3) Single 1) Azygos 2) Not being one of a pair 3) Not one of a pair 4) Occurring singly 5) Single 
• (a.) Odd; having no fellow; not one of a pair; single; as, the azygous muscle of the uvula.
<zoology> Odd; having no fellow; not one of a pair; single; as, the azygous muscle of the uvula. ... (12 Mar 1998) ... 
(az´ĭ-gәs) (ә-zi´gәs) having no fellow; unpaired. Called also azygos.
Az'y·gous adjective [ Greek ...; 
Type: Term Pronunciation: az′ĭ-gŭs, ă-zī′gŭs Definitions: 1. single.
[adj] - (anatomy) occurring singly
azygous Not occurring as one of a pair; having no mate, single, unpaired.
azygos adjective occurring singly; not one of a pair; `the azygous muscle of the uvula`
not being one of a pair; single.