上二段活用
かみにだんかつよう
conjugation (inflection, declension) of nidan verbs (resulting in a stem of either "i" or "u" for every conjugation)
上一段活用 is read as かみいちだんかつよう (kamiichidankatsuyou) and means conjugation (inflection, declension) of ichidan verbs ending in "iru".
かみいちだんかつよう
kamiichidankatsuyou