bowling pin vs tenpin

bowling pin and tenpin both are nouns.

Word	Noun	Adjective	Verb	Adverb
bowling pin	Yes	No	No	No
tenpin	Yes	No	No	No

As nouns, tenpin is a hyponym of bowling pin; that is, tenpin is a word with a more specific, narrower meaning than bowling pin:

bowling pin: a club-shaped wooden object used in bowling; set up in triangular groups of ten as the target
tenpin: one of the bottle-shaped pins used in bowling

Other hyponyms of bowling pin include candlepin, duckpin, headpin, kingpin, ninepin, skittle, skittle pin.

bowling pin (noun)	tenpin (noun)
a club-shaped wooden object used in bowling; set up in triangular groups of ten as the target	one of the bottle-shaped pins used in bowling