battle vs combat

battle and combat both are nouns.

Word	Noun	Adjective	Verb	Adverb
battle	Yes	No	Yes	No
combat	Yes	No	Yes	No

As nouns, combat is a hyponym of battle; that is, combat is a word with a more specific, narrower meaning than battle:

battle: a hostile meeting of opposing military forces in the course of a war
combat: an engagement fought between two military forces

Other hyponyms of battle include Armageddon, pitched battle, naval battle, armed combat, dogfight, assault.

As nouns, combat is a hyponym of battle; that is, combat is a word with a more specific, narrower meaning than battle:

As verbs, battle and combat are synonyms defined as:

battle (noun)	combat (noun)
a hostile meeting of opposing military forces in the course of a war	an engagement fought between two military forces
an energetic attempt to achieve something	the act of fighting; any contest or struggle
an open clash between two opposing groups (or individuals)

battle (verb)	combat (verb)
battle or contend against in or as if in a battle	battle or contend against in or as if in a battle