What does the French word matine mean?

Answer 1

le matin (masc.) means 'the morning' in French; 'la matinée' means the same but indicates the duration, the span of the morning - so to speak, the quantity of time included in a morning.

je me lève tous les matins � sept heures > I get up every morning at 7 (you don't use matinée here)

ça ne va pas durer toute la matinée > it's not going to last all morning (you won't use matin there)

les matines (generally plural) were morning prayers. The word is barely known, but for the popular folk song Frère Jacques, where Brother Jacques is sleeping instead of ringing the bell for the morning prayers.