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Definition of: proto
1. First in rank or time; chief; typical: protomartyr.
2. Primitive; original: prototype.
3. Chem. a Designating the first or lowest member of a series; having the least amount (of an element or radical): protoxide. b Denoting the parent form or source of: protoactinium. Also, before vowels, prot-. [<Gk. prōto- <prōtos first]
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