Learn Romanian: Pompierii au stins incendiul. - The firefighters put out the fire.

The base masculine word is pompier (firefighter). Adding the first -i makes it plural (pompieri, firefighters). The second -i is the masculine plural definite article meaning 'the', giving us pompierii (the firefighters).

What is the dictionary form of the verb stins?

The infinitive is a stinge (to extinguish). It has an irregular past participle, stins. In Romanian, you use this same verb for putting out fires and for turning off lights or electronics, such as a stinge lumina (to turn off the light).

Are incendiu and foc completely interchangeable?

No. While both translate to 'fire', foc is the general word used for the element of fire or controlled fires, like a campfire or a stove. Incendiu specifically refers to an uncontrolled, destructive fire or emergency that requires firefighters.

How do you form the definite noun incendiul?

The base neuter noun is incendiu (fire). To say 'the fire', you need the singular definite article. Because the word already ends in -u, you simply add -l to the end, resulting in incendiul.