Top definition. The lesbian act of gridding the vaginal region against a parteners vaginal region. I walked in on your mom and sister tribbing. Trib sex.
This may involve vulva-to-vulva contact or rubbing the vulva against the partner's thigh, stomach, buttocks, arm, or other body part excluding the mouth. The term tribadism originally encompassed societal beliefs about women's capability of being penetrative sexual partners. It may also involve vaginal penetration by use of the fingers , a dildo or double penetration dildo. The term tribade did not begin to refer exclusively to eroticism between women until Late Antiquity. In English texts, tribade is recorded as early as , in Ben Jonson 's Praeludium Poem X in The Forest ,  to as late as the mid-nineteenth century; it was the most common lesbian term in European texts,  through the proliferation of classical literature, anatomies, midwiferies, sexual advice manuals, and pornography.