1. Part, piece, portion, segment, section, fraction, fragment refer to something that is less than the whole. Part is the general word: part of a house. A piece suggests a part which is itself a complete unit or it may mean an irregular fragment: a piece of pie; a piece of a broken vase. A portion is a part allotted or assigned to a person, purpose, etc.: a portion of food. A segment is often a part into which something separates naturally: a segment of an orange. Section suggests a relatively substantial, clearly separate part that fits closely with other parts to form a whole: a section of a fishing rod, a book. Fraction suggests a less substantial but still clearly delimited part, often separate from other parts: a fraction of his former income. Fragment suggests a broken, inconsequential, incomplete part, with irregular or imprecise outlines or boundaries: a fragment of broken pottery, of information.

Did you mean multiparty?