It's a name used by Lilo for Stitch, a name she chooses based on her love for the Hawaiian word "Aloha" and the sound of the alien's name, "Experiment 626."
The closest meaning to Ahana you might find is the Hawaiian word "Aloha", which means "hello," "goodbye," "love," and "compassion."
Lilo, being a Hawaiian girl, uses the language and cultural values around her to connect with Stitch and give him a name that reflects their bond.