pis ‧ ta ‧ chi ‧ o /pəˈstɑːʃiəʊ, pɪˈstɑːʃiəʊ $ pəˈstæʃioʊ/ BrE AmE noun ( plural pistachios ) [countable]
[ Date: 1400-1500 ; Language: Italian ; Origin: pistacchio , from Latin , from Greek pistakion , from pistake 'pistachio tree' , from Persian pistah ]
a small green nut:
pistachio ice cream