だいいち (とりわけ)
だいいち (とりわけ) · daiichi (toriwake) · JLPT N2 · noun
first
🥇 第 (ordinal marker) + 一 (one) = the one in the first position
第 marks a position in a series and 一 means one, so だいいち covers both 'first' and 'foremost'. とりわけ ('especially, above all') is the second reading, shown by the same word.