To place a crown upon someone's head; to make someone a monarch or give them royal honor.
From en- (causative prefix) + crown. The en- prefix means to put into a state, so encrown means to put a crown on someone, making them crowned.
Encrown appears in Shakespeare and other Renaissance literature—it's a poetic verb that captures the ceremonial solemnity of monarchy, the moment someone becomes royalty through the placement of a symbolic object!
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