In Ackerman v. Loforese, 111 Conn. 700, 151 A. 159 (1930), a tenant attempted to renew pursuant to a renewal clause, but did not succeed in obtaining a new lease. When the landlord later claimed that the tenant had failed in his attempt to renew, the court turned to the distinction between a renewal and an extension.
"A technical difference is frequently recognized . . . between the effect of a covenant for renewal and one for extension, especially as to the effect of retention of possession after the original term, it being held that a stipulation for renewal does not, like a covenant to extend, of itself and alone continue the tenancy for the renewal period, but calls for a new lease, a formal extension of the existing lease or something equivalent thereto . . . . It is recognized that the technical difference may be controlled by the intention of the parties as manifested by the entire lease or by their practical construction of their contract, as by conduct before the controversy arose, whereby the privilege may be construed as one for an extension of term, though the language employed, in a strict technical sense, may signify renewal. The mere fact that the privilege is called one to renew is not conclusive." Id., at 704.