have an early night Definition

early
adj earlier, earliest

1. Characteristic of or near the beginning of (a period of time, period of development, etc).
2. Sooner than others, sooner than usual, or sooner than expected or intended.

Thesaurus: in advance, ahead of time, prematurely, too soon, beforehand; forward, advanced, premature, precocious; Antonym: late.
3. In the near future.
4. In the distant past.

Thesaurus: prehistoric, primitive, primordial, primeval.

Derivative: earliness
noun

Idiom: at the earliest

Not before, and probably later than (a specified time).

Idiom: earlier on

Previously.

Idiom: early and late

At all times.

Idiom: early on

At or near the beginning of a period of time, etc.

Idiom: have an early night

colloq
To go to bed earlier than usual.

Idiom: in the early days

During the first years of (an enterprise, marriage, reign, etc).

Idiom: it's early days

colloq
It is too soon to be able to judge the outcome or expect a result.

Idiom: keep early hours

To go to bed and to get up early regularly.

Etymology: Anglo-Saxon ærlice.