Emily Dickinson Lexicon

six, adj. [OE.]

1. Five plus one; half a dozen; the number next after five.
2. Phrase. “six o'clock”: evening time; 18:00 hours in the twenty-hour period of day.
3. Phrase. “By six” [with ellipsis of “o'clock”]: in the early morning; approaching 6:00 hours in the twenty-hour period of day.