The Collaborative International Dictionary of English v.0.48:

Offset \Off"set`\, n. [Off + set. Cf. Set-off.]
   In general, that which is set off, from, before, or against,
   something; as:
   [1913 Webster]

   1. (Bot.) A short prostrate shoot, which takes root and
      produces a tuft of leaves, etc. See Illust. of
      Houseleek.
      [1913 Webster]

   2. A sum, account, or value set off against another sum or
      account, as an equivalent; hence, anything which is given
      in exchange or retaliation; a set-off.
      [1913 Webster]

   3. A spur from a range of hills or mountains.
      [1913 Webster]

   4. (Arch.) A horizontal ledge on the face of a wall, formed
      by a diminution of its thickness, or by the weathering or
      upper surface of a part built out from it; -- called also
      set-off.
      [1913 Webster]

   5. (Surv.) A short distance measured at right angles from a
      line actually run to some point in an irregular boundary,
      or to some object.
      [1913 Webster]

   6. (Mech.) An abrupt bend in an object, as a rod, by which
      one part is turned aside out of line, but nearly parallel,
      with the rest; the part thus bent aside.
      [1913 Webster]

   7. (Print.) A more or less distinct transfer of a printed
      page or picture to the opposite page, when the pages are
      pressed together before the ink is dry or when it is poor;
      an unitended transfer of an image from one page to
      another; called also setoff.
      [1913 Webster +PJC]

   8. See offset printing.
      [PJC]

   Offset staff (Surv.), a rod, usually ten links long, used
      in measuring offsets.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Offset \Off*set"\, v. t. [imp. & p. p. Offset; p. pr. & vb. n.
   Offsetting.]
   1. To set off; to place over against; to balance; as, to
      offset one account or charge against another.
      [1913 Webster]

   2. To form an offset in, as in a wall, rod, pipe, etc.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Offset \Off"set\, v. i. (Printing)
   To make an offset.
   [1913 Webster]

WordNet (r) 3.0 (2006):

offset
    n 1: the time at which something is supposed to begin; "they got
         an early start"; "she knew from the get-go that he was the
         man for her" [syn: beginning, commencement, first,
         outset, get-go, start, kickoff, starting time,
         showtime, offset] [ant: end, ending, middle]
    2: a compensating equivalent [syn: counterbalance, offset]
    3: a horizontal branch from the base of plant that produces new
       plants from buds at its tips [syn: stolon, runner,
       offset]
    4: a natural consequence of development [syn: outgrowth,
       branch, offshoot, offset]
    5: a plate makes an inked impression on a rubber-blanketed
       cylinder, which in turn transfers it to the paper [syn:
       offset, offset printing]
    6: structure where a wall or building narrows abruptly [syn:
       set-back, setoff, offset]
    v 1: compensate for or counterbalance; "offset deposits and
         withdrawals" [syn: offset, countervail]
    2: make up for; "His skills offset his opponent's superior
       strength" [syn: cancel, offset, set off]
    3: cause (printed matter) to transfer or smear onto another
       surface
    4: create an offset in; "offset a wall"
    5: produce by offset printing; "offset the conference
       proceedings"

Moby Thesaurus II by Grady Ward, 1.0:

203 Moby Thesaurus words for "offset":
   absorb the shock, albertype, analog process, annul, antacid,
   antidote, antipode, antipodes, antipole, antithesis, antonym,
   atone for, balance, ballast, be at cross-purposes, be opposed to,
   behavior pattern, book printing, branch, break the fall,
   bring to nothing, buffer, cancel, cancel out, check,
   chromotypography, chromotypy, chromoxylography, clash, collotype,
   color printing, come to nothing, compensate, compensation,
   conflict, conflict with, consideration, contra, contradict,
   contrapose, contrast with, contravene, controvert, converse,
   counter, counteract, counteractant, counteraction, counteractive,
   counteragent, counterbalance, countercheck, counterirritant,
   counterpoint, counterpoise, counterpole, counterpose, counterterm,
   countervail, counterweigh, counterweight, counterwork, cushion,
   damp, dampen, deaden, digital process, electronography,
   electrostatic printing, equalize, equalizer, equipoise,
   equiponderate, equivalent, even out, even up, feeling, filiation,
   foil, frustrate, give-and-take, graphic arts, gravure,
   halftone engraving, history of printing, hunting, impress,
   impression, imprint, indemnify, input oscillation, invalidate,
   inverse, job printing, juxtapose in opposition, letterpress,
   letterpress photoengraving, line engraving, lithography,
   lithogravure, lithophotogravure, mackle, make amends, make good,
   make restitution, make up, make up for, makeweight, mimeograph,
   negate, negativate, negative, neutralize, neutralizer, nullifier,
   nullify, obverse, offcut, offprint, offset lithography, offshoot,
   onset, oppose, opposite, opposite number, oppugn,
   oscillatory behavior, outweigh, overcorrection of error, overshoot,
   palaeotypography, photo-offset, photochemical process,
   photoengraving, photogelatin process, photographic reproduction,
   photography, photolithography, phototypography, phototypy,
   photozincography, planographic printing, planography,
   play at cross-purposes, preventative, preventive, print, printing,
   printmaking, process, prophylactic, publication, publishing,
   quid pro quo, recompense, redeem, redress, reimburse, reissue,
   relief printing, remedy, repay, reprint, reverse,
   rotary photogravure, rotogravure, run counter to, self-excitation,
   set off, setoff, sheetwork, shoot, show consideration, show mercy,
   show pity, soften, soften the blow, something of value, sprout,
   square, square up, stamp, stencil, stop, stultify, suppress,
   the contrary, the other side, three-color printing, thwart,
   tit for tat, two-color printing, typography, typolithography, undo,
   vis-a-vis, vitiate, void, wood-block printing, xerography,
   xeroprinting, xylotypography, zincography



The Free On-line Dictionary of Computing (30 December 2018):

offset

    An index or position in an array, string, or
   block of memory usually a non-negative integer.

   E.g. the Perl function splice(ARRAY, OFFSET, LENGTH, LIST)
   replaces LENGTH elements starting at index OFFSET in array
   with LIST, where offset zero means the start of the array.

   For an Intel x86 processor with a segmented address space
   the offset is the position of a byte relative to the start
   of the segment.

   (2004-02-27)