minute-by-minute
Etymology
LatinOld FrenchEnglish
Both phrases lean on 'minute', the noun for a sixty-second unit of time, which came into English through Old French from the Latin 'minutus', meaning 'small' or 'made smaller'. Repeating or stacking 'minute' in 'minute-by-minute' and 'by the minute' is a common English pattern for stressing that something is tracked or changing across very short, regular gaps of time.