Keri is a Hebrew term which literally means
"happenstance", "frivolity" or "contrariness" and
has come to mean "seminal emission". The term is generally used in
Jewish law to refer specifically to the regulations and rituals concerning the
emission of semen, whether by nocturnal emission, or by sexual activity. By
extension, a man is said to be a ba'al keri after he has ejaculated without yet
completing the associated ritual cleansing requirements.