day by day

/ˈdeɪ baɪ ˈdeɪ/
adverb
  1. Gradually or slowly over a period of time, one day at a time.
    • We are learning the language day-by-day, without rushing.
    • Her health improved day-by-day after the surgery.
    • The project progressed day-by-day, with small but steady changes.
What does "day by day" mean? | whatsthatwordmean | whatsthatwordmean