A more thorough explanation:

A copyhold tenant is a type of customary tenant who holds land by the custom of the manor. Over time, customary tenants became known as copyhold tenants. They hold their land according to the custom of the manor and have fairly definite terms. The lord has a court where the tenant appears as holding permanently, often heritably. The tenant holds according to the custom of the manor.

For example, in Henry III's time, the process which secured for the tenant in villeinage a written, a registered title, and gave him the name of ‘copyholder,’ was but beginning. The dealings with villein tenements are set forth upon the rolls of the lord's court; the villein tenement is conceived to be holden ‘by roll of court,’ or even ‘by copy of court roll,’ and the mode of conveyance serves to mark off the most beneficial of villeinholds from the most onerous of freeholds.

This example illustrates how copyhold tenants hold their land according to the custom of the manor and have fairly definite terms. They have a written, registered title, and are known as copyholders.