(m) means that a noun is masculine. French nouns have a gender, which is either feminine (like la dame or la lune) or masculine (like l'homme or le soleil).
(M)
My son learned to count up to sixteen at school.Mon fils a appris à compter jusqu’à seize à l’école.
A pronoun is a word that stands in for a noun (e.g., elle, lui).
