7. A method performed by at least one hardware processor executing computer-readable instructions stored on at least one computer-readable storage device, the method comprising: receiving a sibling request to access a combined hierarchical ontology, the combined hierarchical ontology comprising first concepts and corresponding first codes associated with the first concepts by a first terminology and second concepts associated with second codes by a second terminology, wherein the sibling request identifies a specified first concept that is on a particular level of the combined hierarchical ontology and the sibling request specifies a number of levels to traverse the combined hierarchical ontology, the number of levels being greater than one; traversing the combined hierarchical ontology the number of levels specified by the sibling request to identify a common ancestor shared by the specified first concept and a corresponding second concept, wherein the corresponding second concept has a different meaning than the specified first concept and is also on the particular level of the combined hierarchical ontology with the specified first concept; and responding to the sibling request with the corresponding second concept that shares the common ancestor with the specified first concept.
7. A method performed by at least one hardware processor executing computer-readable instructions stored on at least one computer-readable storage device, the method comprising: receiving a sibling request to access a combined hierarchical ontology, the combined hierarchical ontology comprising first concepts and corresponding first codes associated with the first concepts by a first terminology and second concepts associated with second codes by a second terminology, wherein the sibling request identifies a specified first concept that is on a particular level of the combined hierarchical ontology and the sibling request specifies a number of levels to traverse the combined hierarchical ontology, the number of levels being greater than one; traversing the combined hierarchical ontology the number of levels specified by the sibling request to identify a common ancestor shared by the specified first concept and a corresponding second concept, wherein the corresponding second concept has a different meaning than the specified first concept and is also on the particular level of the combined hierarchical ontology with the specified first concept; and responding to the sibling request with the corresponding second concept that shares the common ancestor with the specified first concept. 15. The method of claim 7 , wherein the combined hierarchical ontology has at least one level that is lower than the particular level.