Русско-англо-русский юридический словарь

In law, a reciprocal obligation, also known as a reciprocal agreement is a duty owed by one individual to another and vice versa. It is a type of agreement that bears upon or binds two parties in an equal manner. (Wikipedia)

In my meetings at the G7, we have taken historic steps to demand fair and reciprocal trade that gives Americans a level playing field against other nations. (Independent)

a reciprocal visit (=a visit to the person who visited you) (Macmillan Dictionary)

In Roman & Civil law, innominate contract refers to a contract which is not classifiable under any particular name. In an innominate contract, the law supplies nothing in addition to the express agreement of the parties. This type of contract was developed late in classical Roman law. The agreements did not become operational without at least part performance, even if the agreements were reciprocal. (USLegal)