Suppose \suh-POHZ\ (or \SPOHZ\ if you're from where I'm from) , verb;
1. To assume (something, as for the sake of argument or as part of a proposition or theory
2. To consider something as a possibility suggested or an idea or plan proposed
3. To believe or assume as true; take for granted
4. To think or hold as an opinion
5. To require logically; imply; presuppose
6. Used in the passive: To expect or design; require or permit (followed by an infinite verb)
7. Used without object: To assume something; presume; think
The origin of suppose is Old French supposer ("to assume") and it is first attested in the early 14th century. The Old French word was probably a replacement for *suppondre, which was influenced by poser ("put, place") and derives from Latin supponere ("put or place under"). Supponere is a combination of sub + ponere ("under" + "put, place") and is also the forebear of suppository and supposition.
Suppose originally meant "to assume as the basis of argument" and the meaning "to admit as possible, to believe to be true" dates to the 1520's.