Formerly means at an earlier time than now. Formerly known as, formerly of London, formerly a bank.
Formerly known as is the standard formula for a name change and appears constantly in company records and in music. It is more formal than once and more precise than before, since it always implies the state has changed. Note previously, which means before a stated point rather than before now; and former, the adjective — a former colleague.
1adverbformerlyAt an earlier time than now.
“The hotel was formerly a prison, and some rooms still have bars on the windows.”
formerly is a reference to past time.
From former + -ly.
Etymology from Wiktionary, CC BY-SA
Practised in Time & Calendar