This is the 3060th most frequent Catalan word.
mestra
"Mestra" means "female teacher" in English.
Here, 'mestra' refers to a female teacher specifically in an educational setting.
La mestra ens va ensenyar a llegir.
The teacher taught us to read.
In this case, 'mestra' metaphorically means someone who excels in the subject referred to, here 'patience'.
Ella és una mestra de la paciència.
She is a master of patience.
Here, 'mestra' denotes a female teacher with a specialization in art instruction.