(in Hegelian philosophy) a proposition forming the first stage in the process of dialectical reasoning
a proposition stated or put forward for consideration, especially one to be discussed and proved or to be maintained against objections
related to the absolute idea, in which some assertible proposition (thesis) is necessarily opposed by an equally assertible and apparently contradictory proposition (antithesis) the mutual contradiction being reconciled on a higher level of truth by a third proposition (synthesis)
4. PROSODY an unstressed syllable or part of a metrical foot in Greek or Latin verse.
late Middle English: via late Latin from Greek, literally ‘placing, a setting down, a proposition,’ late 14c., "unaccented syllable or note," from Latin thesis "unaccented syllable in poetry," later "stressed part of a metrical foot," from Greek thesis "a proposition," also "downbeat" (in music), originally "a setting down or placing," from root of tithenai "to place, put, set," from PIE root *dhe- "to put, to do"