Yes. Acceptance typically can come in one of three types:
(1) Express - a direct and absolute outward manifestation of agreement, such as, "I accept your offer."
(2) Implied - the acts of the parties show that the offer has been accepted, such as when both parties to a contract begin to perform the terms of the contract.
(3) Conditional - acceptance is conditional on the happening of something, such as, "I accept your offer so long as you trim my tree in the next two days." By its terms, a conditional acceptance is a counter-offer.