Related vocabulary: day by day, year by year, month by month
week by week
Weekly; on a weekly basis. Our subscriber base has grown week by week, and we're nearly at our target.If you set small goals and work on them day by day and week by week, you'll find that you can accomplish more than you thought possible.
ˌweek by ˈweek
as the weeks pass: Week by week he grew a little stronger.