Definition of "tribade"

Go, cramp dull Mars, light Venus, when he snorts, / Or with thy tribade trine invent new sports; / Thou, nor thy looseness with my making sorts.

a. 1637, Ben Jonson, Præludium

A century later, however, homosexuality among English women seems to have been regarded by the French as common, and Bacchaumont […] added: "Her taste for women will there find attractive satisfaction, for though Paris furnishes many tribades it is said that London is herein superior."

1927, Havelock Ellis, Studies in the Psychology of Sex‎, 3rd edition, volume 2

I roused Zero’s suspicions because I began to behave too much like a woman and he started to watch me warily for signs of the tribade. If he had spied any, or surprised me fingering any of his girls, he would have shot me.

1977, Angela Carter, The Passion of New Eve