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definitions

understand

[uhn-der-stand]
verb (used with object), un·der·stood, un·der·stand·ing.
  1. to perceive the meaning of; grasp the idea of; comprehend: to understand Spanish; I didn't understand your question.
  2. to be thoroughly familiar with; apprehend clearly the character, nature, or subtleties of: to understand a trade.
  3. to assign a meaning to; interpret: He understood her suggestion as a complaint.
  4. to grasp the significance, implications, or importance of: He does not understand responsibility.
  5. to regard as firmly communicated; take as agreed or settled: I understand that you will repay this loan in 30 days.
  6. to learn or hear: I understand that you are going out of town.
  7. to accept as true; believe: I understand that you are trying to be truthful, but you are wrong.
  8. to construe in a particular way: You are to understand the phrase literally.
  9. to supply mentally (something that is not expressed).
verb (used without object), un·der·stood, un·der·stand·ing.
  1. to perceive what is meant; grasp the information conveyed: She told them about it in simple words, hoping they would understand.
  2. to accept tolerantly or sympathetically: If you can't do it, I'll understand.
  3. to have knowledge or background, as on a particular subject: He understands about boats.
  4. to have a systematic interpretation or rationale, as in a field or area of knowledge: He can repeat every rule in the book, but he just doesn't understand.

Origin of understand

before 900; Middle English understanden, understonden, Old English understondan; cognate with Dutch onderstaan. See under-, stand
Related formspre·un·der·stand, verb, pre·un·der·stood, pre·un·der·stand·ing.

Synonyms for understand

1. See know1.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for preunderstanding

understand

verb -stands, -standing or -stood
  1. (may take a clause as object) to know and comprehend the nature or meaning ofI understand you; I understand what you mean
  2. (may take a clause as object) to realize or grasp (something)he understands your position
  3. (tr; may take a clause as object) to assume, infer, or believeI understand you are thinking of marrying
  4. (tr) to know how to translate or readcan you understand Spanish?
  5. (tr; may take a clause as object; often passive) to accept as a condition or provisoit is understood that children must be kept quiet
  6. (tr) to be sympathetic to or compatible withwe understand each other
Derived Formsunderstandable, adjectiveunderstandably, adverb

Word Origin for understand

Old English understandan; related to Old Frisian understonda, Middle High German understān step under; see under, stand
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 preunderstanding

understand

v.

Old English understandan "comprehend, grasp the idea of," probably literally "stand in the midst of," from under + standan "to stand" (see stand). If this is the meaning, the under is not the usual word meaning "beneath," but from Old English under, from PIE *nter- "between, among" (cf. Sanskrit antar "among, between," Latin inter "between, among," Greek entera "intestines;" see inter-).

That is the suggestion in Barnhart, but other sources regard the "among, between, before, in the presence of" sense of Old English prefix and preposition under as other meanings of the same word. "Among" seems to be the sense in many Old English compounds that resemble understand, e.g. underniman "to receive," undersecan "to investigate," underginnan "to begin." It also seems to be the sense still in expressions such as under such circumstances.

Perhaps the ultimate sense is "be close to," cf. Greek epistamai "I know how, I know," literally "I stand upon." Similar formations are found in Old Frisian (understonda), Middle Danish (understande), while other Germanic languages use compounds meaning "stand before" (cf. German verstehen, represented in Old English by forstanden). For this concept, most Indo-European languages use figurative extensions of compounds that literally mean "put together," or "separate," or "take, grasp" (see comprehend). Old English oferstandan, Middle English overstonden, literally "over-stand" seem to have been used only in literal senses.

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

understand

see give to understand.

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