under Definition

under
prep

1a. Below or beneath something but not in contact with it;

Example: under the table
Thesaurus: beneath, below, lower than.
1b. Below or beneath something and in contact with it.

Example: under the book
2. At the foot of.

Example: under the column
3. Less than; short of.

Example: under 10 per cent
4. Lower in rank than.

Thesaurus: beneath, below, lower than, less than, inferior to, subordinate to, subservient to, secondary to.
5. During the reign or administration of.

Example: under Queen Elizabeth II
6. Subjected to, receiving or sustaining.

Example: under consideration
Example: under pressure
7. In the category or classification of.
8. Known by.

Example: goes under the name of
9. According to.

Example: under the terms of the agreement
10. In view of; because of.

Example: under the circumstances
11. Propelled by.

Example: under sail
12. Said of a field: planted with (a particular crop).
13. astrol.
Within the influence of (a particular sign of the zodiac).

adverb

1. In or to a lower place, position or rank.
2. Into a state of unconsiousness.

adj

1. Lower.
2. Subordinate.

Idiom: under lock and key

See under key¹.

Idiom: under one's belt

See under belt¹.

Idiom: under the knife

See under knife.

Idiom: under way

Said of a process, activity, project, etc: in progress; having been instigated.
Thesaurus: going, in motion, in operation, moving, begun, started, launched, afoot.

Said of a vessel: in motion.

Etymology: Anglo-Saxon.