elseif is a concatenation of the programming keywords else and if.

Example:
if exist(external sex organs) then gender=male
elseif PMS==True then gender=female
else gender=/dev/null

IMHO, anything that removes even one keystroke from programming or using a command line interface is a very good thing and if you disagree, you can go back to typing set default = and directory while I type cd and ls

See also VMS-sucks-like-a-dead-cat