What is the difference between a department’s “budget” and its “forecasts”?

OK, not the most momentous topic, but as I listened to Karen Klein, General Counsel, Kayak.com at the recent Ninth Annual SuperConference, she kept referring to the two terms, and showed them repeatedly on her slides.

A budget estimates what a legal department will spend in the coming fiscal year. “Our budget is $14 million for Fiscal Year (FY) 2009.” A forecast, prepared later, revises the budget for FY2009 in light of whatever has been spent through some prior period of time – the first quarter, the first half of the fiscal year – and produces a more knowledgeable estimate of the total spend expected for the year.

A sense of ease, of clarity of expression, of abiding concern resolved, now settles over this blog’s reading public.