A Solicitation is a publicly available document by which a federal agency, corporation, foundation or other nonprofit agency make known its intentions to award discretionary grants, cooperative agreements, or contracts, usually as a result of competition for funds. The solicitation is the roadmap for putting together the proposal. At Stanford, a Solicitation is typically called a Program Announcement (PA).
Each funding agency may use a different term for a solicitation. Some common terms: PA (Program Announcement), Funding Opportunity Announcements (FOA), Requests for Applications (RFA), Broad Area Announcement (BAA), Notices of Funding Availability.