Under  —prep. 1 a in or to a position lower than; below; beneath (under the table). B on the inside of (vest under his shirt). 2 inferior to; less than (no-one under a major; is under 18; was under £20). 3 a subject to; controlled by (under constraint; born under saturn; prospered under him). B undergoing (is under repair). C classified or subsumed in (under two headings). 4 at the foot of or sheltered by (under the cliff). 5 planted with (a crop). 6 powered by (sail, steam, etc.). —adv. 1 in or to a lower position or condition (kept him under). 2 colloq. In or into unconsciousness (put him under). —adj.