day by day; with each passing day
Describes a gradual change or progression as days pass. Often used with verbs of change like 増す, 強まる, 回復する.
See also: 日を追って
The heat is increasing day by day.
His condition is improving with each passing day.
Also means 'day by day', but 日増しに is slightly more literary and less common in casual speech.
Standard kanji-kana mixed spelling.
Variant using 毎; less common but still seen.
Phrase composed of 日 (day), を (object marker), 追う (to follow/chase), and ごとに (each time). Literally 'each time following the day', expressing progression over successive days.