before 950; (noun) Middle Englishknel,Old Englishcynll; (v.) Middle Englishknellen, knyllen,Old Englishcynllan; cognate with Old Norseknylla to beat, strike; akin to Dutchknal bang, knallen to bang, GermanKnall explosion, knallen to explode
O.E. cnyll "sound made by a bell when struck or rung slowly," of imitative origin. Cf. M.H.G. erknellen "to resound," O.E. cnyllan. The Welsh cnull "death-bell" appears to be a borrowing from Eng. For vowel evolution, see bury.