Wiktionary
n. In Thailand, a male-to-female transgender person or person of a third gender, or an effeminate homosexual male.
Wikipedia
Kathoey or katoey is a Thai term that refers to either a transgender woman or an effeminate gay male in Thailand. A significant number of Thais perceive kathoeys as belonging to a third gender, including many kathoeys themselves, while others see them as either a kind of man or a kind of woman. However, when considering transgender women (MtF) as a group in Thai society, most refer to themselves as phuying (Thai: ผู้หญิง "women"), with a minority referring to themselves as phuying praphet song (a "second kind of woman") and only very few referring to themselves as Kathoey. Related phrases include phet thi sam (, "third gender"), and sao praphet song or phu ying praphet song (— both meaning "second-type female"). The word kathoey is of Khmer origin. It is most often rendered as ladyboy or lady boy in English conversation with Thais and this latter expression has become popular across Southeast Asia.