Only when written 相方
Especially common in manzai comedy for the straight man or partner, but can refer to any close companion or counterpart.
See also: 漫才
He serves as the partner of a popular manzai comedian.
He is looking for a manzai partner.
I worked on the project together with my work partner.
partner for the night
Historical or euphemistic term for a companion chosen at a brothel or entertainment district; not used in modern everyday conversation.
In Edo-period pleasure quarters, customers chose a partner for the night.
He chose his childhood friend as his partner and started doing manzai.
The two of them form a duo with the partner they've had since high school.
相棒 is the everyday, general word for a buddy or partner (used for work, police duos, etc.), while 相方 is specifically tied to manzai comedy duos or a chosen companion.
パートナー is a modern loanword for a partner in business, dance, or relationships, whereas 相方 carries a strong association with manzai comedy pairs.
女房役 describes someone who quietly supports a leading figure (like a catcher backing a pitcher), while 相方 is the neutral term for one's manzai or duo partner without implying a supporting role.
相方 refers to one's specific partner (especially in a comedy duo or dance), whereas コンビ refers to the pair as a unit.
相手 broadly means 'the other party' in any interaction (an opponent, customer, etc.), while 相方 specifically means a fixed partner such as one's manzai duo partner or a companion for the evening.
相方 and 相棒 look and sound similar and both mean 'partner', but 相方 is used especially for a comedy duo or dance partner while 相棒 is broader and often implies detective- or crime-story camaraderie.
Used when referring to a person in a formal or countable setting, but for 相方 this is not the usual everyday counter.
Standard kanji spelling for both senses.
Rarely used kanji form.
Compound of 相 (mutual) and 方 (person/direction), literally 'the other party'. The reading あいかた is a kun'yomi compound.