[ in-too; unstressed in-too, -tuh ]
/ ˈɪn tu; unstressed ˈɪn tʊ, -tə /



Mathematics. pertaining to a function or map from one set to another set, the range of which is a proper subset of the second set, as the function f, from the set of all integers into the set of all perfect squares where f(x) = x2 for every integer.

Nearby words

  1. intine,
  2. intitle,
  3. intitule,
  4. intl,
  5. intl.,
  6. into account,
  7. into effect,
  8. into line,
  9. into one's head,
  10. into question

Origin of into

before 1000; Middle English, Old English; see in, to Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for into


/ (ˈɪntuː, unstressed ˈɪntə) /


to the interior or inner parts ofto look into a case
to the middle or midst of so as to be surrounded byinto the water; into the bushes
against; up againsthe drove into a wall
used to indicate the result of a transformation or changehe changed into a monster
maths used to indicate a dividendthree into six is two
informal interested or enthusiastically involved inI'm really into Freud these days
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 into



Old English into, originally in to. The word is a late Old English development to replace the fading dative case inflections that formerly distinguished, for instance, "in the house" from "into the house." To be into something, "be intensely involved in," first recorded 1969 in American English.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with into


In addition to the idioms beginning with into

  • into account
  • into effect
  • into line
  • into one's head
  • into question
  • into the bargain
  • into the blue
  • into the drink
  • into thin air

also see:

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