Nouns ending in -eau are usually masculine.
Is nouveau masculine or feminine?
lenouveau
The feminine form is nouvelle
The rule behind it
93.1% of -eau nouns are masculine
In context
Non, c'est pas mon nouveau petit ami.
No, he's not my new boyfriend.
J'ai entendu les nouvelles à la radio.
I heard the news on the radio.
On construit un nouveau musée dans le centre-ville.
A new museum is being built at the center of the city.