| 1. | beneath and covered by: under a table; under a tree. |
| 2. | below the surface of: under water; under the skin. |
| 3. | at a point or position lower or further down than: He was hit just under his eye. |
| 4. | in the position or state of bearing, supporting, sustaining, enduring, etc.: to sink under a heavy load. |
| 5. | beneath the heading or within the category of: Classify the books under “Fiction” and “General.” |
| 6. | as designated, indicated, or represented by: to register under a new name. |
| 7. | below in degree, amount, etc.; less than: purchased under cost. |
| 8. | below in rank; of less dignity, importance, or the like: A corporal is under a sergeant. |
| 9. | subject to the authority, direction, or supervision of: a bureau functioning under the prime minister. |
| 10. | subject to the instruction or advice of: to study the violin under Heifetz. |
| 11. | subject to the influence, condition, force, etc., of: under these circumstances; born under the sign of Taurus. |
| 12. | protected, controlled, or watched by: under guard. |
| 13. | authorized, warranted, or attested by: under one's hand or seal. |
| 14. | in accordance with: under the provisions of the law. |
| 15. | during the rule, administration, or government of: new laws passed under President Reagan. |
| 16. | in the state or process of: under repair; a matter under consideration. |
| 17. | Nautical. powered by the means indicated: under sail; under steam. |
| 18. | below or beneath something: Go over the fence, not under. |
| 19. | beneath the surface. |
| 20. | in a lower place. |
| 21. | in a lower degree, amount, etc.: selling blouses for $25 and under. |
| 22. | in a subordinate position or condition. |
| 23. | in or into subjection or submission. |
| 24. | beneath or on the underside: the under threads of the embroidery. |
| 25. | lower in position. |
| 26. | lower in degree, amount, etc. |
| 27. | lower in rank or condition. |
| 28. | subject to the control, effect, etc., as of a person, drug, or force: The hypnotist had her subject under at once. The patient was under as soon as he breathed the anesthetic. |
| 29. | go under,
|
| 30. | under wraps. wrap (def. 14). |

| a prefixal use of under, as to indicate place or situation below or beneath (underbrush; undertow); lower in grade or dignity (undersheriff; understudy); of lesser degree, extent, or amount (undersized); or insufficiency (underfeed). |

under
In addition to the idioms beginning with under, also see below (under) par; born under a lucky star; buckle under; come under; cut the ground from under; don't let the grass grow under one's feet; everything but the kitchen sink (under the sun); fall under; false colors, sail under; get under someone's skin; go under; hide one's light under a bushel; hot under the collar; keep under one's hat; knock the bottom out (props out from under); knuckle under; light a fire under; nothing new under the sun; of (under) age; out from under; plow under; pull the rug out from under; put the skids under; six feet under; snow under; sweep under the rug; water over the dam (under the bridge).