turnpike vs pike

turnpike and pike both are nouns.

Word	Noun	Adjective	Verb	Adverb
turnpike	Yes	No	No	No
pike	Yes	No	No	No

As nouns, pike is a hypernym of turnpike; that is, pike is a word with a broader meaning than turnpike:

Other hypernyms of turnpike include expressway, freeway, motorway, state highway, superhighway, throughway, thruway.

turnpike (noun)	pike (noun)
an expressway on which tolls are collected	any of several elongate long-snouted freshwater game and food fishes widely distributed in cooler parts of the Northern Hemisphere
(from 16th to 19th centuries) gates set across a road to prevent passage until a toll had been paid	medieval weapon consisting of a spearhead attached to a long pole or pikestaff; superseded by the bayonet
	a broad highway designed for high-speed traffic
	a sharp point (as on the end of a spear)
	highly valued northern freshwater fish with lean flesh