noun, adverb
three times; thrice
Literal count of three occurrences. Can be used as a noun or adverbially.
彼は三度同じ質問をした。
He asked the same question three times.
adverb
many times; repeatedly; over and over again
Used adverbially to mean 'again and again' or 'many times', not necessarily exactly three. Often found in set phrases like 三度の飯より好き.
三度注意しても彼は聞かなかった。
Even after warning him many times, he wouldn't listen.
彼は三度の飯より釣りが好きだ。
He likes fishing more than eating.
三回 is the standard counter for 'three times' in modern Japanese. 三度 is more literary or emphatic, and also carries the extended meaning of 'many times'.
Compound of 三 (mi, 'three') and 度 (tabi, 'time, occasion'). The reading みたび is a native Japanese reading (kun'yomi).