A Pitaya (pronounced /pɨˈtaɪ.ə/) or pitahaya (English pronunciation: /ˌpɪtəˈhaɪ.ə/) is the fruit of several cactus species, most importantly of the genus Hylocereus (sweet pitayas). These fruit are commonly known as dragon fruit – cf. Chinese huǒ lóng guǒ 火龍果/火龙果 "fire dragon fruit" and lóng zhū guǒ "dragon pearl fruit", or Vietnamese thanh long (green dragon). Other vernacular names are strawberry pear or nanettikafruit. If not otherwise stated, this article's content refers specifically to the pitayas of Hylocereus species, or "dragon fruit".
from wikipedia