The Collaborative International Dictionary of English v.0.48:

Insert \In*sert"\, v. t. [imp. & p. p. Inserted; p. pr. & vb.
   n. Inserting.] [L. insertus, p. p. of inserere to insert;
   pref. in- in + serere to join, connect. See Series.]
   To set within something; to put or thrust in; to introduce;
   to cause to enter, or be included, or contained; as, to
   insert a scion in a stock; to insert a letter, word, or
   passage in a composition; to insert an advertisement in a
   newspaper.
   [1913 Webster]

         These words were very weakly inserted where they will
         be so liable to misconstruction.         --Bp.
                                                  Stillingfleet.
   [1913 Webster]

WordNet (r) 3.0 (2006):

insert
    n 1: a folded section placed between the leaves of another
         publication
    2: an artifact that is inserted or is to be inserted [syn:
       insert, inset]
    3: (broadcasting) a local announcement inserted into a network
       program [syn: cut-in, insert]
    4: (film) a still picture that is introduced and that interrupts
       the action of a film [syn: cut-in, insert]
    v 1: put or introduce into something; "insert a picture into the
         text" [syn: insert, infix, enter, introduce]
    2: introduce; "Insert your ticket here" [syn: insert,
       enclose, inclose, stick in, put in, introduce]
    3: fit snugly into; "insert your ticket into the slot"; "tuck
       your shirttail in" [syn: tuck, insert]
    4: insert casually; "She slipped in a reference to her own work"
       [syn: slip in, stick in, sneak in, insert]

Moby Thesaurus II by Grady Ward, 1.0:

168 Moby Thesaurus words for "insert":
   ad, addendum, addition, admit, advert, advertisement, aside,
   barge in, be admitted, book, break in, breeze in, broadside,
   brochure, burst in, bust in, calendar, carve, catalog, chalk,
   chalk up, check in, chronicle, circular, come barging in,
   come breezing in, come busting in, come in, creep in,
   cross the threshold, crowd in, cut, docket, drag in, drop in,
   ease in, edge in, engrave, enroll, enscroll, enter, episode, file,
   fill in, fill out, flier, flyer, foist in, fudge in,
   gain admittance, get in, go in, go into, grave, handbill,
   have an entree, have an in, hop in, impanel, implant, implant in,
   incise, inculcate, index, infix, infuse, inject, inject in,
   injection, inlay, inoculate, inscribe, insert in, insertion, inset,
   insinuate, insinuate in, insinuation, instill, intercalate,
   intercalation, interjaculate, interject, interjection,
   interlineation, interlocution, interlope, interpolate,
   interpolation, interpose, intervene, introduce, introduce in,
   introduction, intromit, intrude, irrupt, jam in, jot down, jump in,
   list, log, look in, lug in, make a memorandum, make a note,
   make an entry, make out, mark down, matriculate, minute, note,
   note down, obiter dictum, obtrude, pack in, parenthesis, perfuse,
   place upon record, poll, pop in, post, post up, press in, push in,
   put between, put down, put in, put in writing, put on paper,
   put on tape, record, reduce to writing, register, remark, run in,
   sandwich, set down, set foot in, set in, side remark, slip in,
   smuggle in, squeeze in, step in, stick in, supplement, tabulate,
   take down, take in, tape, tape-record, tessera, throw in,
   thrust in, tossing-in, tuck in, videotape, visit, wedge in,
   whip in, work in, worm in, write, write down, write in, write out,
   write up