primary term
primary term. Oil & gas. The option period — set by the habendum clause in an oil-and-gas lease — during which the lessee has the right to search, develop, and produce from the property. • The primary term should be long enough to allow the lessee to evaluate the property and make arrangements to drill. In practice, the primary term may extend for 24 hours or 25 years, depending on how much competition there is for leases in the area. See HABENDUM CLAUSE. Cf. SECONDARY TERM.