From WordNet (r) 2.0 (August 2003) [wn]:
godsend
n : a sudden happening that brings good fortune (as a sudden
opportunity to make money); "the demand for testing has
created a boom for those unregulated laboratories where
boxes of specimen jars are processed lik an assembly
line" [syn: boom, bonanza, gold rush, gravy,
manna from heaven, windfall, bunce]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Godsend \God"send`\ (g[o^]d"s[e^]nd), n.
Something sent by God; an unexpected acquisiton or piece of
good fortune.
[1913 Webster]