late Middle English: from medieval Latin gradualis, from Latin gradus ‘step’. The original sense of the adjective was ‘arranged in degrees’; the noun refers to the altar steps in a church, from which the antiphons were sung
中英語後期。中世ラテン語 gradualis から。ラテン語 gradus「段階」に由来する。形容詞の原義は「段階的に配置された」で、名詞は教会の祭壇の階段(そこで応唱が歌われた)を指す。