noun
1. : a line of demarcation held to distinguish a political party in policy or practice or to limit the action of all loyal party members — usually used in plural
the house … organized quickly along straight party lines — W.V.Shannon
elections … not fought on party lines — Scotsman
cut across all party lines in … search for supporters — Atlantic
2. or party wire : a single telephone circuit connecting two or more subscribers with the exchange
3. : the bounding line between the properties of two or more parties
4.
a. : the complex of policies and attitudes followed or advocated by the Communist party — usually used with the
the party line changed from collaboration with the United States to antagonism — J.C.Cort
Communists adhering to the party line shifted their stand — J.S.Roucek
b. : the complex of principles, policies, and attitudes advocated by or associated with an individual, group, or organization
follows closely the official party line of organized medicine — H.B.Richardson
the whole labor party line — D.C.Coyle