Declaration/ˌdekləˈreɪʃn/ Definition 1 of 4Pro Tip 1/3Formality Level Used in serious or official situations, not casual ones. The mayor's declaration addressed the city's emergency plan. Pro Tip 2/3Public Importance Often involves matters affecting the general public or community. The health department's declaration focused on the vaccination program. Pro Tip 3/3Expect Reactions May lead to discussions, support, or opposition from others. The declaration of the new law sparked a nationwide debate.