HITHERTO
Meaning of HITHERTO in English
hith ‧ er ‧ to /ˌhɪðəˈtuː◂ $ -ər-/ BrE AmE adverb formal
up to this time:
a species of fish hitherto unknown in the West
Longman Dictionary of Contemporary English.
Longman - Словарь современного английского языка.
2012