primer

Etymology 1

From Middle English primer, primere, from Medieval Latin primarius and primarium (“prayer book”) possibly via Anglo-Norman primer (“prayer book”), from prima (“prime the liturgical hour and office”) + -arius and -arium (“forming related objects”). Its use for schoolbooks derived from the late medieval and early modern use of such prayer books to teach reading.

noun

1. (historical, Catholicism ecclesiastical) A prayer or devotional book intended for laity, initially an abridgment of the breviary and manual including the hours of the Virgin Mary, 15 gradual and 7 penitential psalms, the litany, the placebo and dirige forming the office of the dead, and the commendations.
2. (historical, Protestant ecclesiastical) Any of various similar works issued in England for private prayer in accordance with the Book of Common Prayer.
3. A children's book intended to teach literacy: how to read, write, and spell.
   1545, The A.B.C. Primers:
   Four-year-old Elizabeth Finkle-McGraw would receive the Young Lady's Illustrated Primer from her grandfather. Fiona Hackworth would be getting a copy of the Illustrated Primer too, for this had been John Percival Hackworth's crime: He had programmed the matter compiler to place the cockleburs on the outside of Elizabeth's book. 1995, Neal Stephenson, The Diamond Age
4. An introductory text on any subject, particularly basic concepts.
   … The two assets of the book are clear explanation, and a multitude of extremely helpful diagrams, some in two colours, and cutaway photographs; these clearly unravel a difficult subject for the layman, as well as the student engineman for whom the primer is chiefly designed. 1959 March, “New Reading on Railways: The Railwayman's Diesel Manual. By William F. Bolton. G. H. Lake. 7s. 6d.”, in Trains Illustrated, page 172
5. (New Zealand) An elementary school class; an elementary school student. (No longer used.)

Etymology 2

prime + -er.

noun

1. Any substance or device, such as priming wire or blasting cap, used to ignite gunpowder or other explosive.
   The percussion primer, known as the “ 110-grain percussion primer,” contains an igniting charge of 95 grains of black powder in addition to the essential elements of a percussion primer. 1912, United States Army Ordnance Dept, Handbook of the 2.95-inch mountain gun mate/riel and pack outfit, page 17
   Therefore, the shotgun primer is quite self- contained. It consists of a separate metal cup called a battery cup that contains the primer itself. That's why it is considered a two-piece primer. 2003, Sam Fadala, The Gun Digest Blackpowder Loading Manual, page 73
   Take care when handling primers, especially ensure that your fingers are free of oil or dirt. Oil can affect the detonating properties of the primer pellet, and can be the cause of misfires if too much oil gets into the primer. 2016, Steve Sieberts, Gun Digest Shooter's Guide to Competitive Pistol Shooting, page 224
2. (obsolete, rare) A person who primes explosives.
3. A substance used to prime wood, metal, etc. in preparation for painting.
4. A layer of such a substance.
5. A layer of makeup that goes beneath the foundation; undermakeup.
   The undermakeup (primer) should be allowed to dry-set for 30 seconds. Apply foundation over the primer with a sponge using light, careful strokes to blend. Undermakeups come in cream form, sponge-on wands, or sponge-on cream, and as a lotion. 1989, Stan Place, Bobbi Ray Madry, The Art and Science of Professional Makeup, page 95
6. (obsolete, rare) A person who primes wood, metal, etc.
7. (biochemistry, genetics) A molecule which initiates the synthesis of an enzyme, (especially) a single-stranded nucleic acid molecule which initiates DNA replication.
8. (medicine, zoology) A pheromone which interacts first with the endocrine system.
9. A device used to prime an internal combustion engine with gasoline, (especially) in airplanes.
10. A person who prunes trees.

Etymology 3

From Anglo-Norman primer (“first”), from Latin prīmārius (“first”).

adj

1. (obsolete) First in time, initial, early.
2. (obsolete) First in importance, premier.
3. (obsolete, rare) First in position, foremost.