cinquantaine

/sɛ̃.kɑ̃.tɛn/
1.
nounfeminineSing

about fifty

fifty or so

Il y avait une cinquantaine de personnes à la soirée.

There were about fifty people at the party.

2.
nounfeminineSing

the fifties (age range)

being about fifty years old

Elle approche de la cinquantaine.

She is approaching her fifties.