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Thinning in Irish (Caolú): Meaning, Pronunciation, Usage

‘caolú’ also means: dilution · attenuation

The Irish for thinning is caolú, a masculine noun (plural caoluithe). Ag caolú is making thin, from the verb caolaigh.
Updated October 2026Report a mistake

How to say “thinning” in Irish

Irish:
caolú
English:
thinning, dilution, attenuation
Word type:
noun (verbal noun)
Verbal noun of:
caolaigh, to make thin (ag caolú, making thin)
Gender:
masculine, fourth declension
Pronunciation:
“kway-LOO”  /keːˈl̪ˠuː/
Various forms
Plural:
caoluithe
Genitive singular:
caolaithe, an chaolaithe (e.g. riail an chaolaithe, the rule of attenuation)
Genitive plural:
caoluithe, na gcaoluithe (e.g. rialacha na gcaoluithe, the rules of attenuations)

What does “caolú” mean?

“Caolú” has three alternative meanings. The most common comes first.

thinning
The verbal noun of caolaigh: the act of making something thinner, narrower or more slender.Also: narrowing, making thin, tapering.
2 other meanings: dilution or attenuation
2dilution
The act of making a liquid weaker or thinner by adding water or another liquid.Also: diluting, watering down, weakening.
3attenuation
In Irish grammar, the change of a broad consonant to a slender one, as in the genitive of many nouns (bád, báid).Also: palatalization, slenderization, slendering.

“Caolú” as a verbal noun

After ag, caolú means making thin: it is the verbal noun of the verb caolaigh (to make thin). A noun that follows it goes into the genitive.

agat
+
caolúverbal noun
=
ag caolúmaking thin

“Caolú” with the article

The plural of thinning in Irish is caoluithe. Here is caolú after the article (an t-alt), in the singular and the plural.

an caolú
the thinning
No change after an
na caoluithe
the thinning (plural)
Plural: no change after na

“Caolú” in a sentence: Irish examples

Common Irish sentences using caolú, the Irish word for thinning.

Is sampla de chaolú é 'báid'.
'Báid' is an example of attenuation.
Tarlaíonn caolú sa ghinideach uatha go minic.
Attenuation often happens in the genitive singular.
Mhínigh an múinteoir an caolú dúinn inniu.
The teacher explained attenuation to us today.
Ní thuigim rialacha an chaolaithe fós.
I still don't understand the rules of attenuation.
Tá caolú an phéinte riachtanach roimh é a spraeáil.
Thinning the paint is necessary before spraying it.
Bhí caolú le feiceáil sa bhóthar ag an droichead.
The road could be seen narrowing at the bridge.
Tá roinnt caoluithe neamhrialta sa teanga.
There are some irregular attenuations in the language.

Other nouns in Irish

More everyday Irish nouns to learn next.

Thinning in Irish: frequently asked questions

What is the Irish for thinning?

The Irish for thinning is caolú (pronounced “kway-LOO”). It’s a masculine noun and the plural is caoluithe. Depending on context it can also mean dilution or attenuation.

How do you pronounce caolú in Irish?

Caolú is said like “kway-LOO” (IPA /keːˈl̪ˠuː/).

What is the plural of thinning in Irish?

The plural of caolú is caoluithe; with the article, it is na caoluithe. The genitive plural is caoluithe, as in rialacha na gcaoluithe (the rules of attenuations).

Does caolú have more than one meaning?

Yes. Caolú can mean thinning, dilution or attenuation, depending on context; the first is the most common.

Why does caolú change to chaolú or gcaolú?

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

What is the opposite of caolú in grammar?

The opposite is leathnú, broadening, where a slender consonant becomes broad, as in fuil, fola.

Does caolú mean the same as tanú?

Both can mean thinning, but caolú is the grammatical term for attenuation, while tanú is used more for physical thinning or thinning out.

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