Ancient medical texts contain accounts of sexual intercourse.
Tips
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Formal/biological/classical register. Used in zoology (animal mating), classical Chinese medicine, religious/Daoist texts, and academic writing. NOT for everyday speech - use 做爱 ('make love') in modern contexts, or 性交 for clinical use.
memory
交 = 'to interact / join', 媾 = 'to copulate / form a marital alliance' (also in 婚媾, 'to marry'). The 女 (woman) radical in 媾 marks it as a relationship word. Together: 'to join in coupling'.
