brass vs alpha brass

brass and alpha brass both are nouns.

Word	Noun	Adjective	Verb	Adverb
brass	Yes	No	No	No
alpha brass	Yes	No	No	No

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

brass (noun)	alpha brass (noun)
a wind instrument that consists of a brass tube (usually of variable length) that is blown by means of a cup-shaped or funnel-shaped mouthpiece	an alloy of brass and zinc; used mainly for cold working
a memorial made of brass
an ornament or utensil made of brass
impudent aggressiveness
the persons (or committees or departments etc.) who make up a body for the purpose of administering something
the section of a band or orchestra that plays brass instruments
an alloy of copper and zinc