A profusion of terms are currently used to describe free flap wound closure. It is important to broadly standardize nomenclature when embarking on a comparison of functional outcomes between institutions. Therefore, a series of 68 "emergency" (within 24 hours) free flaps performed by a single surgeon were reviewed with respect to a total experience of 188 free tissue transfers to formulate a consistent nomenclature applicable to free flap wound closure in general. The nomenclature presented divides free flap closure into three categories: "primary free flap closure" (12 to 24 hours), "delayed primary free flap closure" (2 to 7 days), and "secondary free flap closure" (after 7 days). This system is analogous to the standard terms "primary," "delayed primary," and "secondary wound closure." It is consistent with known biologic and microbiologic principles of wound closure in general and should provide a simple basis for classifying free flap wound closure. Illustrative examples are presented to highlight the classification scheme.