Idir

Idir primarily translates to "between". It is used to indicate spatial position, time intervals, mutual relationships, and inclusive lists.

Preposition Conjugated Accusative Dative

Overview

Idir requires the accusative in the singular. It requires the dative in the plural.

Uniquely, idir only possesses conjugated forms in the plural. Singular forms (like eadram or eadrat) are considered obsolete.

Pronoun	Form	Contrast Form	Translation
I	-	-	-
You	-	-	-
He	-	-	-
She	-	-	-
We	eadrainn	eadrainne	between us
You (pl)	eadraibh	eadraibhse	between you
They	eatarthu	eatarthusan	between them

Base Idir + Corcaigh

Mutated Idir Corcaigh

Rule No mutation

Base Idir + mná

Mutated Idir mhná

Rule Lenition

Standard Rule (No Mutation) — idir Corcaigh agus Baile Átha Cliath — between Cork and Dublin — When used to indicate distance, timeframes, differences, or contrasts (“between”), it generally causes no lenition.
The Inclusive Rule (Lenition) — idir mhná — among women — When used to mean “among”, “both…and”, or “partly…partly”, it causes lenition.
- Persistence: This lenition is carried over to nouns following agus or is.
- Example: idir fhear is bhean (both man and woman).
- Exception: The DNTLS rule applies (no lenition of d, t, s after agus), e.g., idir shúgradh agus dáiríre (half in fun, half in earnest).
With the Article — idir an t-oileán… — between the island… — In the singular, it follows the rules of the Nominative/Accusative.
- Plural: In the plural, it follows rules for Nominative/Accusative/Dative, often triggering a h-prefix before vowels (e.g., idir na hÉireannaigh — between the Irish).

Question	Meaning	What happens next?	Example
Cé eatarthu	Between whom?	`Indirect`	Cé eatarthu a tharla sé?
Cad eatarthu	Between what?	`Indirect`	Cad eatarthu atá an difríocht?

Spatial — idir Baile Átha Cliath agus Gaillimh — between Dublin and Galway — Indicating location between two points.
Temporal — idir an dó agus an trí — between two and three (o’clock) — Indicating a time interval.
Abstract Separation — cogadh idir Sasana agus an Fhrainc — war between England and France — Indicating a relationship or conflict between entities.

When listing pairs, idir translates to “both… and…” or “X and Y alike”.

Pairs — idir fhear agus bhean — men and women (alike) — Lit. “Between man and woman” (Note the use of the singular noun).
Range — idir sean agus óg — young and old — Covering the whole spectrum.
Construction — idir balla agus ceann — walls and roof — Everything included.

Partly/Partly — idir mhagadh is dáiríre — half in jest, half in earnest — Used to describe mixed states or feelings.
Emotions — idir gháire is ghol — between laughter and weeping.

Privacy (Exclusive) — eadrainn féin an chaint seo — this talk is between ourselves — Meaning “strictly among us” or confidential.
Secret — rún idir mhná — a secret among women.
Superlative (Midst) — an bhean is áille idir Éireannaigh — the most beautiful woman among the Irish — Singling out one from a group.

Progress — idir lámha — in hand / in progress — Something currently being worked on.
Conversation — idir chamáin — in conversation / being discussed.
Meanwhile — idir an dá linn — in the meantime / meanwhile.
Occasionally — idir amanna — now and then / between times.
Indecision — idir eatarthu — half and half / betwixt and between.