This is the 23rd most frequent Catalan word.
fa
"Fa" means "ago."
The word 'fa' is a conjugation of the verb 'fer' ('to do' / 'to make') used to indicate weather-related expressions.
Fa calor avui.
It is hot today.
The word 'fa' expresses the idea of 'ago' when referring to past time.
Va dir que ho va fer fa un mes.
He said that he did it one month ago.
Here, 'fa' is used as a form of 'fer' to imply causation: 'makes' or 'causes'.