Each of the three days preceding Ascension Day (Holy Thursday), during which religious processions take place; a Rogation Day. Chiefly in plural.
Old English se ǣnlīpiga gangdaeg (lit. ‘the single Gang Day’), Middle English the olde gang day denote the Rogation Day usually celebrated on April 25 (sometimes called ‘the major Rogation Day’).
Old English. From gang + day, so called on account of the processions held on these days.