D.C. Mun. Regs. tit. 11, § 1599
1599.1 When used in this chapter, the following term has the meaning ascribed:
1599.2 Nonresidential use - a permitted use in the R-1 District other than a one-family dwelling.
SOURCE: Final Rulemaking published at 41 DCR 5045, 5048 (July 29, 1994).