conjecture (n.) Look up conjecture at
late 14c., "interpretation of signs and omens," from Old French conjecture "surmise, guess," or directly from Latin coniectura "conclusion, interpretation, guess, inference," literally "a casting together (of facts, etc.)," from coniectus, past participle of conicere "to throw together," from com- "together" (see com-) + iacere "to throw" (see jet (v.)). Sense of "forming of opinion without proof" is 1530s.
conjecture (v.) Look up conjecture at
early 15c., from conjecture (n.). In Middle English also with a parallel conjecte (n.), conjecten (v.). Related: Conjectured; conjecturing.