The Collaborative International Dictionary of English v.0.48:

Lag \Lag\, v. i. [imp. & p. p. Lagged; p. pr. & vb. n.
   Lagging.]
   To walk or more slowly; to stay or fall behind; to linger or
   loiter. "I shall not lag behind." --Milton.

   Syn: To loiter; linger; saunter; delay; be tardy.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lag \Lag\, v. t.
   1. To cause to lag; to slacken. [Obs.] "To lag his flight."
      --Heywood.
      [1913 Webster]

   2. (Mach.) To cover, as the cylinder of a steam engine, with
      lags. See Lag, n., 4.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lag \Lag\, n.
   1. One who lags; that which comes in last. [Obs.] "The lag of
      all the flock." --Pope.
      [1913 Webster]

   2. The fag-end; the rump; hence, the lowest class.
      [1913 Webster]

            The common lag of people.             --Shak.
      [1913 Webster]

   3. The amount of retardation of anything, as of a valve in a
      steam engine, in opening or closing.
      [1913 Webster]

   4. A stave of a cask, drum, etc.; especially: (Mach.), one of
      the narrow boards or staves forming the covering of a
      cylindrical object, as a boiler, or the cylinder of a
      carding machine or a steam engine.
      [1913 Webster]

   5. (Zool.) See Graylag.
      [1913 Webster]

   6. The failing behind or retardation of one phenomenon with
      respect to another to which it is closely related; as, the
      lag of magnetization compared with the magnetizing force
      (hysteresis); the lag of the current in an alternating
      circuit behind the impressed electro-motive force which
      produced it.
      [Webster 1913 Suppl.]

   Lag of the tide, the interval by which the time of high
      water falls behind the mean time, in the first and third
      quarters of the moon; -- opposed to priming of the tide,
      or the acceleration of the time of high water, in the
      second and fourth quarters; depending on the relative
      positions of the sun and moon.

   Lag screw, an iron bolt with a square head, a sharp-edged
      thread, and a sharp point, adapted for screwing into wood;
      a screw for fastening lags.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lag \Lag\, a. [Of Celtic origin: cf. Gael. & Ir. lagweak,
   feeble, faint, W. llag, llac, slack, loose, remiss, sluggish;
   prob. akin to E. lax, languid.]
   1. Coming tardily after or behind; slow; tardy. [Obs.]
      [1913 Webster]

            Came too lag to see him buried.       --Shak.
      [1913 Webster]

   2. Last; long-delayed; -- obsolete, except in the phrase lag
      end. "The lag end of my life." --Shak.
      [1913 Webster]

   3. Last made; hence, made of refuse; inferior. [Obs.] "Lag
      souls." --Dryden.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lag \Lag\, n.
   One transported for a crime. [Slang, Eng.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lag \Lag\, v. t.
   To transport for crime. [Slang, Eng.]
   [1913 Webster]

         She lags us if we poach.                 --De Quincey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lag
    n 1: the act of slowing down or falling behind [syn: slowdown,
         lag, retardation]
    2: the time between one event, process, or period and another;
       "meanwhile the socialists are running the government" [syn:
       interim, meantime, meanwhile, lag]
    3: one of several thin slats of wood forming the sides of a
       barrel or bucket [syn: stave, lag]
    v 1: hang (back) or fall (behind) in movement, progress,
         development, etc. [syn: lag, dawdle, fall back, fall
         behind]
    2: lock up or confine, in or as in a jail; "The suspects were
       imprisoned without trial"; "the murderer was incarcerated for
       the rest of his life" [syn: imprison, incarcerate, lag,
       immure, put behind bars, jail, jug, gaol, put
       away, remand]
    3: throw or pitch at a mark, as with coins
    4: cover with lagging to prevent heat loss; "lag pipes"

Moby Thesaurus II by Grady Ward, 1.0:

160 Moby Thesaurus words for "lag":
   afterthought, antedate, arrest, be found wanting, bind, block,
   blockage, bureaucratic delay, cast out, check, closing, collapse,
   come short, con, concluding, confine, dalliance, dally, dallying,
   dawdle, dawdling, dead time, deceleration, decline, delay,
   delayage, delayed reaction, deport, detain, detention, diddle,
   dilatoriness, dillydally, dillydallying, displace, doodle,
   double take, drag, dragging, ease-off, ease-up, eventual, exile,
   expatriate, expel, fail, fall away, fall behind, fall short,
   falter, final, flag, flagging, foredate, gain, get behind,
   goof off, halt, hang back, hang-up, hinder, hindmost, hindrance,
   hold back, hold up, holdup, hysteresis, impede, interim, jailbird,
   jam, keep back, lack, lagging, latest, latter, letdown, letup,
   linger, linger behind, lingering, logjam, loiter, loitering,
   lollygag, lollygagging, lose ground, loser, make late,
   minus acceleration, misdate, mistime, moratorium, not answer,
   not hack it, not make it, not make out, not measure up,
   not stretch, not suffice, obstruct, obstruction, output lag,
   paperasserie, pause, piddle, poke, postdate, process lag,
   procrastinate, procrastination, put off, red tape, red-tapeism,
   red-tapery, relegate, reprieve, respite, retard, retardance,
   retardation, retardment, run short, setback, shilly-shally,
   shilly-shallying, slack-up, slacken, slackening, slow, slow down,
   slow-up, slowdown, slowing, slowing down, slowness, slowup, slump,
   stay, stay of execution, stop, stop short, stoppage, straggle,
   suspension, tarry, tarrying, terminal, throughput, tie-up,
   time constants, time lag, time lead, trail, trail behind,
   transport, ultimate, wait, want, waste time



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

LAG
       Logical Address Group (ION)


The Jargon File (version 4.4.7, 29 Dec 2003):

lag
 n.

    [MUD, IRC; very common] When used without qualification this is synonymous
    with netlag. Curiously, people will often complain ?I'm really lagged?
    when in fact it is their server or network connection that is lagging.


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

netlag
lag

    A condition that occurs when the delays in the
   IRC network, a MUD connection, a telnet connection, or
   any other networked interactive system, become severe enough
   that servers briefly lose and then reestablish contact,
   causing messages to be delivered in bursts, often with delays
   of up to a minute.  (Note that this term has nothing to do
   with mainstream "jet lag").

   [Jargon File]

   (1996-06-21)