Pet peeve.
"Sorry, she's on annual leave. Do you want her voice mail?"
No she almost certainly isn't. She's on holiday using some of her annual leave entitlement.
Annual leave would be leave you take once a year, every year.
Annual leave entitlement is the entitlement to leave that one has in a given year.
This drives me nuts because it feels like the "myself" hypercorrection. "Annual leave" isn't a posher word for "holiday"; they aren't even synonyms.
As you were.