Binary and Twain

Binary noun - A system of two stars that revolve around each other under their mutual gravitation.

Twain and binary are semantically related In some cases you can use "Twain" instead a noun "Binary".

Twain noun - Two things of the same or similar kind that match or are considered together.

Binary and twain are semantically related in two of something topic. You can use "Binary" instead the word "Twain" as a noun or an adjective.