noun
Formal or literary term for trade between parties, often implying mutual exchange. Less common in everyday speech than 貿易 (ぼうえき) or 取引 (とりひき).
両国は互市協定を結んだ。
The two countries concluded a trade agreement.
歴史的に、この港は互市の中心地だった。
Historically, this port was a center of commerce.
Sino-Japanese compound from 互 (mutual) and 市 (market), literally 'mutual market'. The exact historical derivation is uncertain, but it follows a common pattern for formal trade terms.