This is the 5020th most frequent French word.
tes
"Tes" means "your" (plural, informal).
The word 'tes' is a possessive adjective, used here before the noun 'livres' to indicate possession by the second-person singular subject 'you'.
Tes livres sont sur la table.
Your books are on the table.
Here, 'tes' is a possessive adjective indicating that 'devoirs' belongs to the person spoken to, for the second person singular form.
As-tu terminé tes devoirs ?
Have you finished your homework?
In this sentence, 'tes' is used to show that the 'idées' being appreciated belong to the person being addressed using the second person singular form.