This is the 8880th most frequent Spanish word.
tienes
"Tienes" means "you have."
Here, 'tienes' is the conjugation of 'tener' (to have) in the second person singular present tense and is used to inquire about possession ('a moment').
¿Tienes un momento para hablar?
Do you have a moment to talk?
In this sentence, 'tienes' is used in a subordinate clause in a temporal context to indicate when someone possesses ('time').
Cuando tienes tiempo, ponte en contacto conmigo.
When you have time, get in touch with me.
Here, 'tienes' is part of a necessity expression ('to have to') combined with 'que' to convey obligation.