What is the X in X-mas?
1802, "the higher or upper portion of a town," from up + town. As this usually was the residential portion of a town (especially a port) the word had overtones of that. Specific meaning "more prosperous area of town" is recorded from 1946.
Informed; au courant; aware of the situation: Ballard was up to speed now (1980s+)
bring someone up to speed