gravy

Concise Oxford English Dictionary © 2008 Oxford University Press:
gravy/ˈɡreɪvi/

▶noun (pl. gravies)

• 1 the fat and juices exuding from meat during cooking.

  ■ a sauce made from these juices together with stock and other ingredients.

• 2 informal, chiefly N. Amer. unearned or unexpected money.

– phrases
gravy train informal a situation in which someone can easily make a lot of money.

– origin ME: perh. from a misreading (as gravé) of OFr. grané, prob. from grain ‘spice’, from L. granum ‘grain’.