D defs.my
Entry 2 senses Webster, 1913

Unionism

/yo͞on'-yən-ĭzˌ-əm/ · Un·ion·ism · IPA /jˈuːnjənˌɪzəm/
01 n. The sentiment of attachment to a federal union, especially to the federal union of the United States.
  1. 1.
    The sentiment of attachment to a federal union, especially to the federal union of the United States.
  2. 2.
    The principles, or the system, of combination among workmen engaged in the same occupation or trade.