ENGLISH
REFERENCE

reason

n. C / U
A1 Beginner Oxford US //ˈɹizən// UK //ɹˈiːzən// rea·son Archaic General-service

n. the fact or event that explains why something happens or why someone does something. You use it to give a cause for an action.

n. a cause, explanation, or justification for an action or event. Often used to denote the logical basis for a conclusion or belief.


SIMPLE

The main reason for the delay was the heavy rain.

CONTEXTUAL

She gave her boss a good reason for being late to the morning meeting.

COMPLEX

Philosophers often distinguish between the cause of a physical event and the reason for a human action, suggesting that the latter implies a level of conscious intent.

Synonyms
Etymology 1

From Middle English resoun, reson, from Anglo-Norman raisun (Old French raison), from Latin ratiō, from ratus, past participle of reor (“reckon”), ultimately from Proto-Indo-European h₂reh₁- (“to think”), reanalysed root of h₂er- (“to put together”). Displaced native Middle English reden (found in compounds), from Old English rǣden (“condition, stipulation, calculation, direction”), from the same Proto-Indo-European source (compare West Frisian reden (“reason”), Dutch reden (“reason”)). Doublet of ration and ratio.

Etymology 2

From Middle English reason, reson, resen, rasen, from Old English ræsn (“beam, rafter, ceiling, wall panel”), probably from Proto-West Germanic raʀn (“house”), from Proto-Germanic razną (“house, dwelling”), from Proto-Indo-European *h₁erh₁- (“to rest”).

Usage

Often followed by the preposition 'for' or a 'that' clause. When used to mean the human power of logic, it is typically uncountable.

Pitfall

the reason because I am latethe reason why I am lateLearners often use 'because' after 'reason', but 'why' or 'that' is the correct relative adverb to introduce the explanation.

Idioms5 entries

© 2026 English Reference