Definition of fab:
(adj) :
short for
fabulous (great or spectacular).
[The American Heritage Dictionary of the English Language, third edition, Houghton Mifflin Company, p. 652 (ISBN 0-395-44895-6)]; (in composition) short for
fabricated, as in
pre-fab
(n) :
a manufacturing plant which fabricates items, particularly
silicon chips
"hundreds were put out of work when the chip fab shut down."
"it uses digital data from a computer to "fab" products and models of new products."