substubEtymologyFrom sub- + stub.nounA subheading below a stub (stub head) in a table; a stub subordinate to another stub.“The first column on the left is the stub column. Its heading is referred to as the stub head. A stub is a title for a row of (horizontal) data. Should a stub column contain substubs, then the substubs are indented two or three spaces to show that they are subordinate to the stub item.”