rotor shaft vs rotor head

rotor shaft and rotor head both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotor shaft	Yes	No	No	No
rotor head	Yes	No	No	No

As nouns, rotor shaft and rotor head are synonyms defined as:

rotor shaft and rotor head: the axis around which the major rotor of a helicopter turns

rotor shaft (noun)	rotor head (noun)
the axis around which the major rotor of a helicopter turns	the axis around which the major rotor of a helicopter turns