What is the definition of thesis?

Thesis is derived from Greek, in which the Word has the sense of a proposition. The essential meaning of thesis (which will here be treated as roughly interchangeable with hypothesis) has thus remained stable from its ancient Greek origins into today's English: a thesis is a proposition, affirmation, or assertion that can occur in literature, rhetoric, science, mathematics, or even everyday talk.

Before attempting a more formal definition of thesis, it will help to consider the following examples of theses:

• Some examples of theses:
• Literature: To be or not to be, that is the question.
• Rhetoric: The death penalty is barbaric.
• Science: All organisms evolved from simpler organisms due to natural selection and mutation.
• Ordinary Conversation: The weather will be pleasant tomorrow...