main road vs pike

main road and pike both are nouns.

Word	Noun	Adjective	Verb	Adverb
main road	Yes	No	No	No
pike	Yes	No	No	No

As nouns, pike is a hyponym of main road; that is, pike is a word with a more specific, narrower meaning than main road:

main road (noun)	pike (noun)
a major road for any form of motor transport	any of several elongate long-snouted freshwater game and food fishes widely distributed in cooler parts of the Northern Hemisphere
	medieval weapon consisting of a spearhead attached to a long pole or pikestaff; superseded by the bayonet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