It's also used to flavour a kind of festive brioche:

https://en.wikipedia.org/wiki/Tsoureki

And liqueur:

https://en.wikipedia.org/wiki/Mastika

Etymologically, it looks like the root word means "chew", and i would guess that mastikha is named for that, rather than vice versa:

https://en.wiktionary.org/wiki/%CE%BC%CE%B1%CF%83%CF%84%CE%B...