Thesis
late Middle English (in thesis (sense 3)): via late Latin from Greek, literally ‘placing, a proposition’, from the root of tithenai ‘to place’.
wiktionary
From Late Middle English thesis(“lowering of the voice”) [1] and also borrowed directly from its etymonLatin thesis(“proposition, thesis; lowering of the voice”), from Ancient Greek θέσῐς(thésis, “arrangement, placement, setting; conclusion, position, thesis; lowering of the voice”), from τῐ́θημῐ(títhēmi, “to place, put, set; to put down in writing; to consider as, regard”) [2] [3] (ultimately from Proto-Indo-European *dʰeh₁-(“to do; to place, put”)) + -σῐς(-sis, suffix forming abstract nouns or nouns of action, process, or result) The English word is a doublet of deed.
Sense 1.1 (“proposition or statement supported by arguments”) is adopted from antithesis. [2] Sense 1.4 (“initial stage of reasoning”) was first used by the German philosopher Johann Gottlieb Fichte (1762–1814), and later applied to the dialectical method of his countryman, the philosopher Georg Wilhelm Friedrich Hegel (1770–1831).
The plural form theses is borrowed from Latin thesēs, from Ancient Greek θέσεις(théseis).
etymonline
thesis (n.)
late 14c., "unaccented syllable or note," from Latin thesis "unaccented syllable in poetry," later (and more correctly) "stressed part of a metrical foot," from Greek thesis "a proposition," also "downbeat" (in music), originally "a setting down, a placing, an arranging; position, situation," from reduplicated form of PIE root *dhe- "to set, put." Sense in logic of "a formulation in advance of a proposition to be proved" is first recorded 1570s; that of "dissertation presented by a candidate for a university degree" is from 1650s.
