Merriam-Webster's Collegiate® Dictionary, 11th Edition
LEAK
I. verb
Etymology: Middle English leken, liken, from or akin to Middle Dutch leken; akin to Old English hlec leaky, Old High German zelehhan, Old Norse leka to leak and probably to Old English leccan to moisten, Middle Irish legaid it melts
Date: 14th century
intransitive verb
1. to enter or escape through an opening usually by a fault or mistake , to let a substance or light in or out through an opening,
2. to become known despite efforts at concealment , to be the source of an information leak, transitive verb to permit to enter or escape through or as if through a leak, to give out (information) surreptitiously , leaker noun
II. noun
Date: 15th century
1. a crack or hole that usually by mistake admits or lets escape, something that permits the admission or escape of something else usually with prejudicial effect, the act, process, or an instance of leaking, an act of urinating, leakproof adjective