The Collaborative International Dictionary of English v.0.48:

Primer \Prim"er\, n. [Originally, the book read at prime, the
   first canonical hour. LL. primae liber. See Prime, n., 4.]
   1. Originally, a small prayer book for church service,
      containing the little office of the Virgin Mary; also, a
      work of elementary religious instruction.
      [1913 Webster]

            The primer, or office of the Blessed Virgin. --Bp.
                                                  Stillingfleet.
      [1913 Webster]

   2. A small elementary book for teaching children to read; a
      reading or spelling book for a beginner.
      [1913 Webster]

            As he sat in the school at his prymer. --Chaucer.
      [1913 Webster]

   3. (Print.) A kind of type, of which there are two species;
      one, called long primer, intermediate in size between
      bourgeois and small pica [see Long primer]; the other,
      called great primer, larger than pica.
      [1913 Webster]

   Note: Great primer type.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Primer \Prim"er\, n.
   One who, or that which, primes; specifically, an instrument
   or device for priming; esp., a cap, tube, or water containing
   percussion powder or other compound for igniting a charge of
   gunpowder.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Primer \Prim"er\, a. [OF. primer, primier, premier, F. premier.
   See Premier.]
   First; original; primary. [Obs.] "The primer English kings."
   --Drayton.
   [1913 Webster]

   Primer fine (O. Eng. Law), a fine due to the king on the
      writ or commencement of a suit by fine. --Blackstone.

   Primer seizin (Feudal Law), the right of the king, when a
      tenant in capite died seized of a knight's fee, to receive
      of the heir, if of full age, one year's profits of the
      land if in possession, and half a year's profits if the
      land was in reversion expectant on an estate for life; --
      now abolished. --Blackstone.
      [1913 Webster]

WordNet (r) 3.0 (2006):

primer
    n 1: an introductory textbook
    2: any igniter that is used to initiate the burning of a
       propellant [syn: fuse, fuze, fusee, fuzee, primer,
       priming]
    3: the first or preliminary coat of paint or size applied to a
       surface [syn: flat coat, ground, primer, priming,
       primer coat, priming coat, undercoat]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "primer":
   abecedarium, abecedary, alphabet, alphabet book, and arithmetic,
   basics, battledore, blasting cap, cap, casebook, chromogen, coat,
   coat of paint, coating, color, color filter, color gelatin,
   colorant, coloring, dead-color, detonating powder, detonator,
   distemper, drier, dye, dyestuff, electric detonator,
   elementary education, elements, exercise book, exploder,
   exterior paint, first principles, first steps, flat coat,
   flat wash, floor enamel, fulminating mercury, fuse, gradus,
   grammar, ground, hornbook, induction, initiation, interior paint,
   introduction, manual, manual of instruction, medium,
   mercury fulminate, opaque color, outlines, paint, percussion cap,
   pigment, primacord, prime coat, priming, principia, principles,
   propaedeutic, reader, reading, rudiments, schoolbook, speller,
   spelling book, squib, stain, t, tempera, text, thinner, tinction,
   tincture, transparent color, turpentine, turps, undercoat,
   undercoating, vehicle, wash, wash coat, workbook, writing