A more thorough explanation:

Feu farm is a type of land tenure in Scots law where a person holds land in exchange for an annual payment called feu duty. This type of tenure was converted to a freehold in 2000.

John owns a feu farm where he pays an annual feu duty of £500 to the landowner in exchange for the right to use the land. This type of tenure is common in Scotland.

Feu duty is the annual rent paid by the tenant of a feu. It is also known as ground annual.

Sarah is the tenant of a feu and pays an annual ground annual of £100 to the landowner. This payment gives her the right to use the land for a specified period of time.

These examples illustrate how feu farm and feu duty work in Scots law. They show that a person can hold land in exchange for an annual payment, and that this payment is known as feu duty or ground annual.