conjunction
besides; furthermore; moreover
Formal or literary conjunction used to add another point, similar to さらに or その上. Often appears in written arguments or speeches.
彼は優秀な研究者であり、かつまた優れた教育者でもある。
He is an excellent researcher and, moreover, an outstanding educator.
この計画は費用がかかり、かつまた時間
This plan is costly and, furthermore, requires time.
さらに is more common and neutral in register, while かつまた is more formal and literary.
その上 is slightly less formal than かつまた and more common in everyday speech.
Compound of 且つ (katsu, 'and also') and 又 (mata, 'again, also'), reinforcing the additive meaning.