a·ro·ma·tase 
(ə-rōmə-tāz′, -tāz′)
(ə-rōmə-tāz′, -tāz′)n.
A key enzyme in the biosynthesis of steroids, especially in the conversion of androgens to estrogens.
[AROMAT(IC) (because the enzyme increases the number of aromatic carbon rings in the molecular structure of the compounds upon which it acts) + –ASE.]