Definition of party:

part of speech: adjective

That concerns not the whole; in her., used with reference to the division of a field or charge.

part of speech: noun

A number of persons united in opinion or design in opposition to others belonging to the same body or community; a faction; one concerned or interested in an affair; one of two litigants; a particular person- but improperly so applied; a cause or a side; a select company or assembly; a small detachment of troops drawn from the main body.