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definitions

spec

[spek]
noun
  1. Usually specs. specification(def 2).
  2. speculation.
adjective
  1. built, done, bought, etc., as a speculation: the construction of spec houses.
verb (used with object), spec'd or specked or specced, spec'·ing or speck·ing or spec·cing.
  1. to provide specifications for: Their newest truck was spec'd by a computer.
Idioms
  1. on spec, made, built, or done with hopes of but no assurance of payment or a sale; without commitment by a client or buyer: ad illustrations done on spec; luxury homes built on spec and sold before completion.

Origin of spec

An Americanism dating back to 1785–95; by shortening
Related formsspec·’er, speck·er, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for on spec

spec

noun
  1. on spec as a speculation or gambleall the tickets were sold so I went to the theatre on spec
adjective
  1. (prenominal) Australian and NZ speculativea spec developer

Word Origin for spec

C19: short for speculation or speculative
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for on spec

spec

n.

short for specification, 1956. Related: Specs.

Online Etymology Dictionary, © 2010 Douglas Harper
Idioms and Phrases with on spec

on spec

Done on a speculative basis; with no assurance of profit. For example, We didn't design our house; the builder built it on spec. The use of spec as an abbreviation for speculation dates from the late 1700s.

spec

see on spec.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.