be on loan
if something is on loan, it has been lent to a person or organization in an official way – often used about a library book or a work of art
on loan (from somebody/something)
if something or someone is on loan, they have been borrowed

[TahlilGaran] Dictionary of Contemporary English ▲

lend (also loan especially American English) to let someone borrow money or something that belongs to you for a short time:
Can you lend me $20?
Did you lend that book to Mike?
The documents were loaned by the local library.
let somebody use something/let somebody have something to let someone use something that belongs to you for a short time, especially a room, a house, or something big and expensive:
Some friends are letting us use their house while they are on vacation.
Dad said he’d let me have his car for the weekend.
be on loan if something is on loan, it has been lent to a person or organization in an official way – often used about a library book or a work of art:
The museum has an exhibition of paintings on loan from the Louvre.
According to the computer, this book is still out on loan.

[TahlilGaran] English Thesaurus ▲