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Bisector in Irish (Déroinnteoir): Meaning, Pronunciation, Usage

The Irish for bisector is déroinnteoir, a masculine noun (plural déroinnteoirí).
Updated October 2026Report a mistake

How to say “bisector” in Irish

Irish:
déroinnteoir
English:
bisector
Word type:
noun
Gender:
masculine
Pronunciation:
“DAY-rin-tyohr”  /ˈdʲeːˌrˠən̪ʲtʲoːɾʲ/
Various forms
Plural:
déroinnteoirí (bisectors)
Genitive singular:
déroinnteora, an déroinnteora (e.g. fad an déroinnteora, length of the bisector)
Genitive plural:
déroinnteoirí, na ndéroinnteoirí (e.g. pointe trasnaithe na ndéroinnteoirí, point of intersection of the bisectors)

What does “déroinnteoir” mean?

bisector
A line or plane that divides an angle or line segment into two equal parts.Also: angle bisector, perpendicular bisector.

“Déroinnteoir” with the article

The plural of bisector in Irish is déroinnteoirí. Here is déroinnteoir after the article (an t-alt), in the singular and the plural.

an déroinnteoir
the bisector
No change after an
na déroinnteoirí
the bisectors
Plural: no change after na

“Déroinnteoir” in a sentence: Irish examples

Common Irish sentences using déroinnteoir, the Irish word for bisector.

Tarraing déroinnteoir na huillinne seo.
Draw the bisector of this angle.
Roinneann an déroinnteoir an uillinn ina dhá leath.
The bisector divides the angle in half.
Is líne dhíreach é déroinnteoir.
A bisector is a straight line.
Casann na déroinnteoirí ag pointe amháin sa triantán.
The bisectors meet at one point in the triangle.
Úsáid compás chun an déroinnteoir a tharraingt.
Use a compass to draw the bisector.
Tomhais fad an déroinnteora le rialóir.
Measure the length of the bisector with a ruler.
Tá an pointe sin ar an déroinnteoir ingearach.
That point is on the perpendicular bisector.

Other nouns in Irish

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Bisector in Irish: frequently asked questions

What is the Irish for bisector?

The Irish for bisector is déroinnteoir (pronounced “DAY-rin-tyohr”). It’s a masculine noun and the plural is déroinnteoirí.

How do you pronounce déroinnteoir in Irish?

Déroinnteoir is said like “DAY-rin-tyohr” (IPA /ˈdʲeːˌrˠən̪ʲtʲoːɾʲ/).

What is the plural of bisector in Irish?

The plural of déroinnteoir is déroinnteoirí; with the article, na déroinnteoirí means “the bisectors”. The genitive plural is déroinnteoirí, as in pointe trasnaithe na ndéroinnteoirí (point of intersection of the bisectors).

Why does déroinnteoir change to dhéroinnteoir or ndéroinnteoir?

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

How is déroinnteoir formed?

It comes from the prefix dé- (two) and roinnteoir (divider), from the verb déroinn, to bisect.

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