Pivot (6)
'pivot' is the definition.
(I know that fulcrum is a type of pivot)
This is all the clue.
(Other definitions for fulcrum that I've seen before include "The point on which a lever turns" , "Point against which a lever rests" , "Pivot on which a lever moves" , "prop" , "Support; fixed point for a lever" .)
'pivot' is the definition.
(I know that pivot can be written as swivel)
This is the entire clue.
(Other definitions for swivel that I've seen before include "Kind of chair with seat that turns horizontally" , "Rotating coupling" , "swinging" , "Turn on a chair, say" , "Connection allowing rotation" .)