undated
adjective
uk/ˌʌnˈdeɪtɪd/ usnot having a known or written date:
The memo is undated but may have been written as early as May.
undated photo/photograph/letter I received an undated letter saying that there would be a delay in opening the account.
The Pettigrew St. business district is shown in this undated photo.
FINANCE
(of a bond or other investment) not having a date at which it can be redeemed (= exchanged for cash):
The cash flow from an undated bond can be viewed as a continuous annuity.