Trade (also known as Chow) is a gay slang term originating from Polari and refers to the (usually) casual partner of a gay man or to the genre of such pairings. Men falling in the category of "trade" are not gay-identified. Historically the motivations may at times include a desire for emotional fulfillment and admiration, but the term often refers to a straight man who partners with a gay man for economic benefit, either through a direct cash payment or through other, more subtle means (gifts, tuition payments, etc.). Trade originally referred to casual sex partners, regardless of sexuality as many gay and bisexual men were closeted, but evolved to imply the gay partner is comparatively wealthy and the partner who is trade is economically deprived. Examples of this include wealthy Englishmen finding partners among deprived Cockneys in 1930s London; traveling men finding partners in places such as Rio de Janeiro, Brazil, and Bangkok, Thailand and locals picking up military personnel who are generally seen as being physically appealing and eager for extra income or benefits.
More modern usage has centered on any casual sexual encounter between men, and as an adjective to refer to any male considered masculine and/or sexually appealing.
Often, the terms trade and rough trade are treated as synonymous. Often the attraction for the gay male partner is finding a dangerous, even thuggish, partner who may turn violent. That is not to say that people necessarily desire to be physically hurt, but the danger of seeking a partner in a public park, restroom, or alleyway may be exciting. Another variation is in comparison to regular trade, rough trade is more likely to be working-class laborers with less education and more physical demands of their work, therefore with a body developed naturally rather than in a gym. They may have a less polished or cleancut style than an office worker or professional businessman.
Royal favourites may at times have been trade. The label could perhaps be applied to George Villiers, 1st Duke of Buckingham, the favourite of James I of England.