Sac is masculine (Larousse, 2005, p. 928)
Reference:
(2005). Larousse French-English English-French Dictionary. Paris, France: Larouuse,
masculine: le sac à dos
un sac
Feminine
directeur → masculine directrice→ feminine
It is feminine.
The French word "sac" is masculine.
masculine: le sac à dos
Un sac (masculine noun) de couchage.
"Sac l'école" is masculine in French. The word "sac" (bag) is masculine, so it determines the gender of the entire phrase.
The word "sac" in French is masculine. So, it uses masculine definite article "le" and indefinite article "un".
A schoolbag is "un cartable" in French; cartable is a masculine noun.
un sac
Feminine
A handbag is "un sac", which is masculine. I'm not sure what you mean by asking how to express it in the feminine.
"Sac" is a masculine noun in French.
masculine
La salade is feminine