"Due date"

Ind. Code § 6-8.1-1-4, under Chapter 1. Definitions and Applicability.

Ind. Code § 6-8.1-1-4

Sec. 4. "Due date" means the last date on which a particular act, such as filing a return or making a payment, may be performed and still be on time. If an extension of time is allowed for performing a particular act, the "due date" is the last day of the extension period. As added by Acts 1980, P.L.61, SEC.1.