Propeller (3)
'propeller' is the definition.
(an oar helps propel a boat)
This is the entire clue.
(Other definitions for oar that I've seen before include "It ends in blade" , "Propelling blade" , "Rowing implement" , "Manual boat propeller" , "Rower" .)
'propeller' is the definition.
(I know that screw is a type of propeller)
This is the entire clue.
(Other definitions for screw that I've seen before include "Fastener with a tapered threaded shank" , "wages" , "Metal fastener" , "Fastener; propeller" , "shaft" .)