1. [n]  a failure to maintain a higher state
2. [n]  a mistake resulting from inattention
3. [n]  a break or intermission in the occurrence of something; "a lapse of three weeks between letters"
4. [v]  go back to bad behavior; "Those who recidivate are often minor criminals"
5. [v]  drop to a lower level; as in one's morals or standards
6. [v]  end, at least for a long time; "The correspondence lapsed"
7. [v]  pass into a specified state or condition; "He sank into Nirvana"
8. [v]  pass by, as of time
9. [v]  let slip; "He lapsed his membership"

1. \Lapse\, n. [L. lapsus, fr. labi, p. p. lapsus, to slide,
   to fall: cf. F. laps. See {Sleep}.]
   1. A gliding, slipping, or gradual falling; an unobserved or
      imperceptible progress or passing away,; -- restricted
      usually to immaterial things, or to figurative uses.
            The lapse to indolence is soft and imperceptible.
                                                  --Rambler.
            Bacon was content to wait the lapse of long
            centuries for his expected revenue of fame. --I.
                                                  Taylor.
   2. A slip; an error; a fault; a failing in duty; a slight
      deviation from truth or rectitude.
            To guard against those lapses and failings to which
            our infirmities daily expose us.      --Rogers.
   3. (Law) The termination of a right or privilege through
      neglect to exercise it within the limited time, or through
      failure of some contingency; hence, the devolution of a
      right or privilege.
   4. (Theol.) A fall or apostasy.
   

2. \Lapse\, v. i. [imp. & p. p. {Lapsed}; p. pr. & vb. n.
   {Lapsing}.]
   1. To pass slowly and smoothly downward, backward, or away;
      to slip downward, backward, or away; to glide; -- mostly
      restricted to figurative uses.
            A tendency to lapse into the barbarity of those
            northern nations from whom we are descended.
                                                  --Swift.
            Homer, in his characters of Vulcan and Thersites,
            has lapsed into the burlesque character. --Addison.
   2. To slide or slip in moral conduct; to fail in duty; to
      fall from virtue; to deviate from rectitude; to commit a
      fault by inadvertence or mistake.
            To lapse in fullness Is sorer than to lie for need.
                                                  --Shak.
   3. (Law)
      (a) To fall or pass from one proprietor to another, or
          from the original destination, by the omission,
          negligence, or failure of some one, as a patron, a
          legatee, etc.
      (b) To become ineffectual or void; to fall.
                If the archbishop shall not fill it up within
                six months ensuing, it lapses to the king.
                                                  --Ayliffe.
   

3. \Lapse\, v. t.
   1. To let slip; to permit to devolve on another; to allow to
      pass.
            An appeal may be deserted by the appellant's lapsing
            the term of law.                      --Ayliffe.
   2. To surprise in a fault or error; hence, to surprise or
      catch, as an offender. [Obs.]
            For which, if be lapsed in this place, I shall pay
            dear.                                 --Shak.
   

A single assignment language for the Manchester dataflow machine.

["A Single Assignment Language for Data Flow Computing", J.R.W. Glauert, M.Sc Diss, Victoria U Manchester, 1978].