1. A method for aggregating property attribute values across two or more schemas associated with two or more data sources, the method comprising: receiving at least a first schema and a second schema, wherein the first schema includes at least a first property described by a plurality of static attributes and a plurality of contextual attributes associated with a first plurality of contextual attribute values, and wherein the second schema includes the first property described by a property reference to the first property from the first schema that includes a second plurality of contextual attribute values for the plurality of contextual attributes, wherein a contextual attribute value for a contextual attribute in the first schema is different than the contextual attribute value for the contextual attribute in the second schema; receiving a request for an aggregated first property description of the first property based on the first schema and the second schema; building, at a computing device, the aggregated first property description from the plurality of static attributes and the plurality of contextual attributes associated with contextual attribute values selected from either the first plurality of contextual attribute values or the second plurality of contextual attribute values, wherein the plurality of static attributes from the first schema are included in the aggregated first property description; and communicating the aggregated first property description.