join battle vs contend

join battle and contend both are verbs.

Word	Noun	Adjective	Verb	Adverb
join battle	No	No	Yes	No
contend	No	No	Yes	No

As verbs, contend is a hypernym of join battle; that is, contend is a word with a broader meaning than join battle:

Other hypernyms of join battle include fight, struggle.

join battle (verb)	contend (verb)
engage in a conflict	to make the subject of dispute, contention, or litigation
	have an argument about something
	maintain or assert
	compete for something; engage in a contest; measure oneself against others
	be engaged in a fight; carry on a fight
	succeed in doing, achieving, or producing (something) with the limited or inadequate means available