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Base angle in Irish (Bonnuillinn): Meaning, Pronunciation, Usage

The Irish for base angle is bonnuillinn, a feminine noun (plural bonnuillinneacha).
Updated October 2026Report a mistake

How to say “base angle” in Irish

Irish:
bonnuillinn
English:
base angle
Word type:
noun
Gender:
feminine
Pronunciation:
“BUN-il-in”  /ˈbˠʊnˌɪlʲɪnʲ/
Various forms
Plural:
bonnuillinneacha (base angles)
Genitive singular:
bonnuillinne, na bonnuillinne (e.g. méid na bonnuillinne, size of the base angle)
Genitive plural:
bonnuillinneacha, na mbonnuillinneacha (e.g. suim na mbonnuillinneacha, sum of the base angles)

What does “bonnuillinn” mean?

base angle
In geometry, an angle at the base of a figure such as a triangle.Also: angle at the base, base angle of a triangle.

“Bonnuillinn” with the article

The plural of base angle in Irish is bonnuillinneacha. Here is bonnuillinn after the article (an t-alt), in the singular and the plural.

an bhonnuillinn
the base angle
Lenition: b becomes bh after an (feminine noun)
na bonnuillinneacha
the base angles
Plural: no change after na

“Bonnuillinn” in a sentence: Irish examples

Common Irish sentences using bonnuillinn, the Irish word for base angle.

Tomhais an bhonnuillinn sa triantán seo.
Measure the base angle in this triangle.
Tá an dá bhonnuillinn cothrom le chéile.
The two base angles are equal.
Is ionann bonnuillinneacha triantáin chomhchosaigh.
The base angles of an isosceles triangle are equal.
Scríobh méid na bonnuillinne ar an léaráid.
Write the size of the base angle on the diagram.
Is bonnuillinn ghéar í seo.
This is an acute base angle.
Fuair mé an bhonnuillinn mícheart sa cheist.
I got the base angle wrong in the question.
Cé mhéad céim atá i ngach bonnuillinn?
How many degrees are in each base angle?

Other nouns in Irish

More everyday Irish nouns to learn next.

Base angle in Irish: frequently asked questions

What is the Irish for base angle?

The Irish for base angle is bonnuillinn (pronounced “BUN-il-in”). It’s a feminine noun and the plural is bonnuillinneacha.

How do you pronounce bonnuillinn in Irish?

Bonnuillinn is said like “BUN-il-in” (IPA /ˈbˠʊnˌɪlʲɪnʲ/).

What is the plural of base angle in Irish?

The plural of bonnuillinn is bonnuillinneacha; with the article, na bonnuillinneacha means “the base angles”. The genitive plural is bonnuillinneacha, as in suim na mbonnuillinneacha (sum of the base angles).

Why does bonnuillinn change to bhonnuillinn or mbonnuillinn?

Irish changes the start of some words after certain words. After mo (my) bonnuillinn becomes mo bhonnuillinn (lenition), and after ár (our) or i (in) it becomes ár mbonnuillinn (eclipsis).

How is 'bonnuillinn' formed?

It combines 'bonn' (base) and 'uillinn' (angle, elbow), so it means the angle at the base of a figure.

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