Binary and Duple

Binary adjective - Consisting of two members or parts that are usually joined.

Duple and binary are semantically related in part topic. In some cases you can use "Duple" instead an adjective "Binary". popular alternative

Duple adjective - Consisting of or involving two parts or components usually in pairs.

Binary and duple are semantically related in part topic. You can use "Binary" instead an adjective "Duple", if it concerns topics such as two-fold, in a pair.