Targets are what you aim commands at.
A target is always one of the below:
(object name) -- if it's nearby.
#(object number) -- to avoid ambiguity, some cmds don't require #'s.
*(player name) -- for when they're not nearby.
+(Group name) -- for when it's not nearby.
HERE -- translates to the rooms number.
ME -- translates to user's number.
HOME -- translates to the user's home's room number.
BACK -- translates to the room number the BUILDER previous visited.
THERE -- translates to the room number the builder just dug.
RETURN -- sends the USER back wherever they came in from.