spear thrower vs dart thrower

spear thrower and dart thrower both are nouns.

Word	Noun	Adjective	Verb	Adverb
spear thrower	Yes	No	No	No
dart thrower	Yes	No	No	No

As nouns, spear thrower and dart thrower are synonyms defined as:

spear thrower and dart thrower: a device resembling a sling that is used in various primitive societies to propel a dart or spear

Other synonyms of spear thrower include throwing board, throwing stick.

spear thrower (noun)	dart thrower (noun)
a device resembling a sling that is used in various primitive societies to propel a dart or spear	a device resembling a sling that is used in various primitive societies to propel a dart or spear