I. adjective Date: before 12th century happening, done, or used by night or every night, of or relating to the night or every night, II. adverb Date: 15th century every night
NIGHTLY
Meaning of NIGHTLY in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012