adverb
earlier; -est
at or near the beginning of a period of time or a process, activity, series, etc.
before the usual or expected time
early on
at or during an early point or stage
Early on originated in British English. Some American writers have objected to it, but it is now very common in the U.S. Note that unlike early, early on can appear at the beginning of a sentence.
adjective
earlier; -est
existing or happening near the beginning of a period of time
b always used before a noun :happening near the beginning of a process, activity, series, etc.
coming or happening before the usual or expected time
doing something before the usual time or before others usually do
The expression the early bird catches/gets the worm means that people who start or arrive before others are more likely to succeed. - opposite late
early days (yet)
Brit - used to say that it is too soon to know how something will turn out
early hours
get/make an early start
to get started on a journey, activity, etc., early in the day
make an early night of it
to go home or go to bed early