Sweet Home Chapter of Communities for a Great Oregon, an entity representing the interests of families dependent upon the forest-products industry, small landowners, logging companies, and others (plaintiffs) filed suit in federal district court against Bruce Babbitt, in his official capacity as Secretary of the Interior (Secretary), the U.S. Fish and Wildlife Service, and others (defendants) challenging the meaning of the term “harm” as defined in regulations promulgated pursuant to the Endangered Species Act (ESA). Section 9 of the ESA makes it unlawful for a person to "take" a threatened or endangered species, and the ESA in turn defined "taking" to mean, among other things, "harm." The Secretary promulgated a regulation defining the word "harm" in the prohibition on takings to include significant habitat modification or degredation that actually kills or injures wildlife. The plaintiffs alleged that the application of the “harm” regulation to the red-cockaded woodpecker, an endangered species, and the northern spotted owl, a threatened species, had injured plaintiffs economically because they could not conduct logging activities where the animals were located. The district court granted defendants’ motion for summary judgment and held the Secretary possessed the authority to define “harm” as he wished. The court of appeals reversed, relying on a canon of statutory construction that a word is defined by the words around it and finding that the words around "harm" in the statute referred only to the application of direct force against the "taken" animal. The United States Supreme Court granted certiorari.