'Prototype,' 'primary,' and 'first' are all distant cousins — three expressions of PIE *pro- (before).
A prefix meaning 'first,' 'earliest,' 'original,' or 'primitive,' derived from Greek and used to form words indicating temporal or developmental priority — the earliest form of something.
From Greek 'prōtos' (πρῶτος, first, foremost, earliest), superlative of 'pro' (before, in front), from PIE *per- (forward, before, first). The root *per- is one of the most productive in the Indo-European family: it generated Latin 'prīmus' (first, source of 'prime,' 'primary,' 'premier'), Latin 'prae-' (before, source of 'pre-' words), Latin 'pro' (forward, for), Sanskrit 'pra-' (forth, forward), and Greek 'pro' (before) and 'prōtos' (first). As a scientific prefix, 'proto-' means 'first' or 'original' — the earliest or most primitive form of something: 'prototype' (first mould), 'protocol' (first sheet of a scroll, then first rules), 'proton' (the primary particle). The prefix entered
The word 'protein' — the most fundamental class of biological molecules — comes from Greek 'prōteîos' (πρωτεῖος, of the first quality), from 'prôtos' (first). The Dutch chemist Gerardus Johannes Mulder suggested the name in 1838, and the Swedish chemist Jöns Jacob Berzelius agreed, naming these molecules 'proteins' because they seemed to be of 'primary' importance to life. The molecules that build every living cell are named, literally, 'the first things