To chronicle an event is to record it as it happens, and a chronicle is a record of those events. If your grandmother took the time to chronicle the details of her 1910 journey to Japan, you can read her chronicle today.
To chronicle something is to describe past or current events. Chronicle is related to chronological and comes from the Greek ta khronika, which means “annals of time.” Events are usually chronicled in the order in which they occurred. The noun chronicle is a record of things that happened — told in chronological order, like the diary you kept in elementary school. It is a chronicle of those years.