Proposal
Part of speech: noun
Definition: That which is proposed, or propounded for consideration or acceptance; a scheme or design; terms or conditions proposed; offer; as, to make proposals for a treaty of peace; to offer proposals for erecting a building; to make proposals of marriage. The offer by a party of what he has in view as to an intended business transaction, which, with acceptance, constitutes a contract.
Proposition
Part of speech: verb
Definition: To propose a plan to.To propose some illicit behaviour to, often sexual in nature
Part of speech: noun
Definition: The act of offering (an idea) for consideration.An idea or a plan offered.The terms of a transaction offered.The content of an assertion that may be taken as being true or false and is considered abstractly without reference to the linguistic sentence that constitutes the assertion.In some states, a proposed statute or constitutional amendment to be voted on by the electorate.An assertion so formulated that it can be considered true or false.As a special case, textbooks often, and papers sometimes, label an assertion which is provably true, but not important enough to be a theorem, a proposition. Normally this is part of a numerical reference system (Proposition 3.2, Lemma 3.3, Theorem 3.4)