Full Idea
In beginning philosophy, the first beginning is from definitions.
Gist of Idea
Definitions are the first step in philosophy
Source
Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.15)
Book Reference
Hobbes,Thomas: 'Metaphysical Writings', ed/tr. Calkins,Mary Whiton [Open Court 1905], p.35
A Reaction
Note that he doesn't say that definitions are the aim of philosophy, as some analysts might think.