A more thorough explanation:

Definition: A legal term in Law French that means "to have and to hold." It is often used in the habendum clause of a legal instrument, such as a deed or will, to define the extent of the interest being granted and any conditions affecting the grant.

Example: In a deed, the habendum clause might read: "To John Smith, his heirs and assigns, to have and to hold the property described herein, subject to any easements or restrictions of record."

This example illustrates how the phrase "a aver et tener" is used in the context of a legal instrument to define the extent of the interest being granted and any conditions affecting the grant.

Example: In an oil-and-gas lease, the habendum clause might define how long the interest granted to the lessee will extend. For example, it might provide for a primary term of 5 years, during which the lessee has no obligation to develop the premises, and a secondary term of "so long thereafter as oil and gas produced" once development takes place.

This example illustrates how the phrase "a aver et tener" is used in the context of an oil-and-gas lease to define the duration of the lease and any conditions affecting the grant.