“Thesis: Three meanings may be distinguished: a. a long essay or treatise presented for a degree; b. a proposition to be proved; c. the unstressed syllable of a metrical foot (e.g. thesis itself is a trochaic word on which the second syllable is unstressed).”
Excerpted from: Cuddon, J.A. The Penguin Dictionary of Literary Terms and Literary Theory. New York: Penguin, 1992.