Pistachio \Pis*ta"chio\, n.

1. The small anacardiaceous tree, of southern Europe and Asia Minor, which bears the pistachio nut.

2. (Cookery) The flavor of the pistachio nut, or an ice or confection flavored with it.

3. Pistachio green.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Pistachio \Pis*ta"chio\, n. [It. pistacchio (cf. Sp. pistacho, F. pistache), fr. L. pistacium, Gr. ?, ?, fr. Per. pistah. Cf. Fistinut.]

(Bot.) The nut of the Pistacia vera, a tree of the order Anacardiace[ae], containing a kernel of a pale greenish color, which has a pleasant taste, resembling that of the almond, and yields an oil of agreeable taste and odor; -- called also pistachio nut. It is wholesome and nutritive. The tree grows in Arabia, Persia, Syria, and Sicily. [Written also pistachia.]

Source: Webster's Revised Unabridged Dictionary (1913)