Midsummer Eve

noun Chiefly British.
  1. the evening preceding Midsummer Day: formerly believed to be a time when witches and other supernatural beings caused widespread mischief.

Origin of Midsummer Eve

late Middle English word dating back to 1400–50
Also called Midsummer Night, St. John's Eve, St. John's Night.

St. John's Eve

Also called St. John's Night.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018