This command removes name entries: fields, frames, structures and links between the frames and items. The basic command rm removes a name entry which is not referred from other frames. Instead you can also remove referred items with the flag -ref when all the links are deleted automatically. Also with the flag -fr an item can be deleted if the reference is the last one.
Example:
NDA> load boston.dat ... # remove a field from a frame, but do not delete a field if it is # referred from other frames NDA> rm -fr boston boston.crim ... # remove a frame and all the fields under it NDA> rm boston ... # remove a structure NDA> rm som1