PRIMER

I. noun Etymology: Middle English, layperson's prayer book, from Anglo-French, from Medieval Latin primarium, from Late Latin, neuter of primarius primary Date: 14th century a small book for teaching children to read, a small introductory book on a subject, a short informative piece of writing, II. noun Date: 1819 a device for priming, material used in priming a surface, a molecule (as a short strand of RNA or DNA) whose presence is required for formation of another molecule (as a longer chain of DNA)