From the Late Latin name Dominicus, a derivative of dominus ‘lord’. It was used mainly by Roman Catholics, in honour of St Dominic (1170–1221), founder of the Dominican order of monks, but has enjoyed wider appeal since the 1970s.
English and Scottish: patronymic from the personal name John. As an American family name, Johnson has absorbed patronymics and many other derivatives of this name in continental European languages. (For forms, see Hanks and Hodges 1988.)