Receipt of notice means the time the bank received enough information (whether in writing or orally) to be able to identify the customer, why the customer believes an error occurred and the transaction(s) in question.
From section
205.11 :
(b) Notice of error from consumer—(1) Timing; contents. A financial institution shall comply with the requirements of this section with respect to any oral or written notice of error from the consumer that:
(i) Is received by the institution no later than 60 days after the institution sends the periodic statement or provides the passbook documentation, required by §205.9, on which the alleged error is first reflected;
(ii) Enables the institution to identify the consumer's name and account number; and
(iii) Indicates why the consumer believes an error exists and includes to the extent possible the type, date, and amount of the error, except for requests described in paragraph (a)(1)(vii) of this section.
I have always interpreted the timeframes to mean the 45th or 90th day after the day notice was received, so the day of receipt would be day 0.