This research addressed the question of whether children understand proper names differently from descriptions. We examined how children extend these two types of expressions from an initial object (a truck) owned by the experimenter to two identical objects created by transforming the initial object, both owned by the experimenter. Adults and 5/6-year-olds extended a name ("Tommy") to only one post-transformation object, but extended a description ("my truck") to "both" objects. Adults and 7-year-olds (but not 5/6-year-olds) also extended a description modeled as a name ("'called' My Truck") to only one object. Like adults, children understand that proper names identify unique individuals, but that descriptions identify properties.