polearm vs Lochaber ax

polearm and Lochaber ax both are nouns.

Word	Noun	Adjective	Verb	Adverb
polearm	Yes	No	No	No
Lochaber ax	Yes	No	No	No

As nouns, Lochaber ax is a hyponym of polearm; that is, Lochaber ax is a word with a more specific, narrower meaning than polearm:

polearm: a close combat weapon in which the main fighting part of the weapon is fitted to the end of a long shaft, typically of wood, thereby extending the user's effective range.
Lochaber ax: a battle-ax formerly used by Scottish Highlanders

Other hyponyms of polearm include poleax, poleaxe, furket, musket rest.

polearm (noun)	Lochaber ax (noun)
a close combat weapon in which the main fighting part of the weapon is fitted to the end of a long shaft, typically of wood, thereby extending the user's effective range.	a battle-ax formerly used by Scottish Highlanders