Etymology: Middle English, adverb & preposition, from Old English; akin to Old High German untar under, Latin inferus situated beneath, lower, infra below, Sanskrit adha
Date: before 12th century
1. in or into a position below or beneath something
2. below or short of some quantity, level, or limit <$10 or under> — often used in combination <understaffed> 3. in or into a condition of subjection, subordination, or unconsciousness <put the patient under for surgery> 4. down to defeat, ruin, or death <businesses going under> 5. so as to be covered <buried under by the avalanche> II. preposition Date: before 12th century 1. below or beneath so as to be overhung, surmounted, covered, protected, or concealed by <under sunny skies> <a soft heart under a stern exterior> <under cover of darkness> 2. a. subject to the authority, control, guidance, or instruction of <served under the general> <under the terms of the contract> <a program that runs under any operating system> b. receiving or undergoing the action or effect of <under pressure> <courage under fire> <under the influence of alcohol> <the image of a point under a mapping> <under oath> 3. a. within the group or designation of <under this heading> b. having as name or title <traveling under an alias> 4. less or lower than (as in size, amount, or rank); especially falling short of a standard or required degree <under the legal age> <under par> III. adjective Date: 13th century 1. a. lying or placed below, beneath, or on the ventral side — often used in combination <underlip> b. facing or protruding downward 2. lower in rank or authority ; subordinate 3. lower than usual, proper, or desired in amount, quality, or degree — often used in combination <an under-dose of medicine>
New Collegiate Dictionary. 2001.