:hash collision: [from the technical usage] n. (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}.
-- The AI Hackers Dictionary