to assume (something), as for the sake of argument or as part of a proposition or theory: Suppose the distance to be one mile.
2.
to consider (something) as a possibility suggested or an idea or plan proposed: Suppose we wait until tomorrow.
3.
to believe or assume as true; take for granted: It is supposed that his death was an accident.
4.
to think or hold as an opinion: What do you suppose he will do?
5.
to require logically; imply; presuppose: The evidence supposes his presence near the scene.
6.
(used in the passive) to expect or design; require or permit (fol. by an infinitive verb): The machine is supposed to make noise. I'm not supposed to run fast.
–verb (used without object)
7.
to assume something; presume; think.
Origin: 1275–1325; ME supposen < OF supposer, equiv. to sup-sup-+ poser to pose1; cf. ML suppōnere to suppose, L: to substitute, place below
sup·pose (sə-pōz') v.
sup·posed, sup·pos·ing, sup·pos·es
v.
tr.
To assume to be true or real for the sake of argument or explanation: Suppose we win the lottery.
To believe, especially on uncertain or tentative grounds: Scientists supposed that large dinosaurs lived in swamps.
To consider to be probable or likely: I suppose it will rain.
To imply as an antecedent condition; presuppose: "Patience must suppose pain"(Samuel Johnson).
To consider as a suggestion: Suppose we dine together.
v.
intr. To imagine; conjecture.
[Middle English supposen, from Old French supposer, alteration (influenced by poser, to place) of Medieval Latin suppōnere, from Latin, to put under : sub-, sub- + pōnere, to place; see apo- in Indo-European roots.]
sup·pos·ing (sə-pō'zĭng) conj. Assuming that: Supposing we're right, what should we do?
[suh-poh-zing] 
zɪŋ