(Roman Catholicism) A devout salutation often used as a prelude to certain set prayers; the traditional response is Et cum spiritu tuo.
Etymology
From Latin dominusvobiscum ‘the lord be with you’, apparently taken from the Bible (e.g. Ruth 2:4 ‘And behold, Boaz came from Bethlehem, and said unto the reapers, The LORD be with you. And they answered him, The LORD bless thee’).