Ohio Rev. Code Ann. § 5721.30
As used in sections 5721.30 to 5721.43 of the Revised Code:
(E)
(1) With respect to a sale of tax certificates under section 5721.32 of the Revised Code, and except as provided in division (E)(2) of this section, "certificate redemption price" means the certificate purchase price plus the greater of the following:
(F) With respect to a sale or transfer of tax certificates under section 5721.33 of the Revised Code, "certificate redemption price" means the amount equal to the sum of the following:
(J) "Certificate interest period" means, with respect to a tax certificate sold under section 5721.32 or 5721.42 of the Revised Code and for the purpose of accruing interest under section 5721.41 of the Revised Code, the period beginning on the date on which the certificate is purchased and, with respect to a tax certificate sold or transferred under section 5721.33 of the Revised Code, the period beginning on the date of delivery of the tax certificate, and in either case ending on one of the following dates: