Bandha' (bond, arrest) is a term for the "body locks" in Hatha Yoga, treated under the heading of mudra. Specific bandhas are:
Mula Bandha, contraction of the perineum
Uddiyana bandha, contraction of the abdomen into the rib cage
Jalandhara Bandha, tucking the chin close to the chest
Maha Bandha, combining all three of the above bandhas