WordNet (r) 3.0 (2006):

shell out
    v 1: administer or bestow, as in small portions; "administer
         critical remarks to everyone present"; "dole out some
         money"; "shell out pocket money for the children"; "deal a
         blow to someone"; "the machine dispenses soft drinks" [syn:
         distribute, administer, mete out, deal, parcel
         out, lot, dispense, shell out, deal out, dish
         out, allot, dole out]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "shell out":
   accord, administer, afford, allot, allow, award, bestow, bestow on,
   budget, communicate, confer, cost, cost out, deal, deal out,
   disburse, dish out, dispense, dole, dole out, donate, expend,
   extend, fork out, gift, gift with, give, give freely, give out,
   go through, grant, hand out, heap, help to, impart, incur costs,
   invest, issue, lavish, lay out, let have, mete, mete out, offer,
   open the purse, outlay, pay, pay out, pour, present, proffer,
   put out, rain, render, run through, schedule, serve, shower,
   sink money in, slip, snow, spend, splurge, squander, tender,
   throw money around, vouchsafe, yield



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

shell out
 vi.

    [Unix] To spawn an interactive subshell from within a program (e.g., a
    mailer or editor). ?Bang foo runs foo in a subshell, while bang alone
    shells out.?


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

shell out

   [Unix] To spawn an interactive subshell from within a program
   (e.g. a mailer or editor).  "Bang foo runs foo in a subshell,
   while bang alone shells out."

   [Jargon File]

   (1995-05-11)