hash collision

hash collision n.  [from the techspeak] (var. `hash
   clash') When used of people, signifies a confusion in associative
   memory or imagination, especially a persistent one (see
   {thinko}).  True story: One of us [ESR] was once on the phone
   with a friend about to move out to Berkeley.  When asked what he
   expected Berkeley to be like, the friend replied: "Well, I have
   this mental picture of naked women throwing Molotov cocktails, but
   I think that's just a collision in my hash tables."  Compare
   {hash bucket}.