The verb suppose has 5 senses (first 3 from tagged texts)
1. (47) suppose, say -- (express a supposition; "Let us say that he did not tell the truth"; "Let's say you had a lot of money--what would you do?")
2. (31) think, opine, suppose, imagine, reckon, guess -- (expect, believe, or suppose; "I imagine she earned a lot of money with her new novel"; "I thought to find her in a bad state"; "he didn't think to find her in the kitchen"; "I guess she is angry at me for standing her up")
3. (17) speculate, theorize, theorise, conjecture, hypothesize, hypothesise, hypothecate, suppose -- (to believe especially on uncertain or tentative grounds; "Scientists supposed that large dinosaurs lived in swamps")
4. presuppose, suppose -- (take for granted or as a given; suppose beforehand; "I presuppose that you have done your work")
5. presuppose, suppose -- (require as a necessary antecedent or precondition; "This step presupposes two prior ones")