threeway (English) comes from English three, from Middle English thre, from Old English þrī, from Proto-West Germanic þrīʀ, from Proto-Germanic þrīz, from Proto-Indo-European *tréyes.
threeway (English): a sexual act involving three people
Definitions
a sexual act involving three people
Ancestry of “threeway”, step by step
threeway traces back through two separate lines of ancestry.