| Part of speech | common noun |
|---|---|
| Hyphenation | tri·an·gul·o |
| Singular | Plural | |
|---|---|---|
| Nominative | triangulo | trianguloj |
| Accusative | triangulon | triangulojn |
| Afrikaans | driehoek |
|---|---|
| Catalan | triangle |
| Czech | trojúhelník |
| Danish | trekant |
| Dutch | driehoek |
| English | triangle; trigon |
| Finnish | kolmio; kolmikulmio |
| French | triangle |
| German | Dreieck |
| Greek | τρίγωνο |
| Hungarian | háromszög |
| Icelandic | þríhyrningur |
| Italian | triangolo |
| Jamaican Patois | chrayanggl |
| Latin | triangulum; trigonium |
| Norwegian | trekant |
| Papiamento | triángulo |
| Polish | trójkąt |
| Portuguese | triângulo |
| Russian | треугольник |
| Saterland Frisian | Trjokaant |
| Scots | triangle |
| Spanish | triángulo |
| Swahili | pembetatu |
| Swedish | trehörning; triangel |
| Thai | รูปสามเหลี่ยม |
| Turkish | üçgen |
| Welsh | triongl |
| West Frisian | trijehoek |