An externally threaded fastener whose threaded portion is of one nominal diameter, no. 10 (0.190 in.) (5 mm) or larger. it has a round unthreaded neck or shank all or part of which is of greater diameter than the threaded portion. the head is not designed to be held or driven with an inserted drivers. a locking feature may be incorporated in the design of the head or threads. for items with a thread diameter smaller than no. 10 (0.190 in.) (5 mm) and those items with an inserted drive head, use screw, shoulder. for items which are no. 10 (0.190 in.) (5 mm) or larger in size and are both shouldered and have an externally relieved body, use bolt, externally relieved body. excludes thumbscrew.