Fugue

noun

1 Music a contrapuntal composition in which a short melody or phrase (the subject) is introduced by one part and successively taken up by others and developed by interweaving the parts.
2 Psychiatry a state or period of loss of awareness of one's identity, often coupled with flight from one's usual environment, associated with certain forms of hysteria and epilepsy.

Learned the second meaning from today's NYT, as in "dissociative fugue". Still can't understand why it is a 'fugue.'

Maybe this helps:

ORIGIN late 16th cent.: from French, or from Italian fuga, from Latin fuga ‘flight,’ related to fugere ‘flee.’