A classification of ichidan (one-row) verb conjugation whose stem is on the "e" vowel row. Often used for verbs ending in -eru; a term appearing in classical/historical grammar and detailed conjugation explanations.
下一段活用は、語幹が「え」段になる一段動詞の活用様式を指します。
Shimo-ichidan conjugation refers to the ichidan verb pattern whose stem is on the "e" row.
教科書では「食べる」は下一段活用（現代では一段活用）として説明されることが多い。
Textbooks often describe "taberu" as shimo-ichidan conjugation (in modern terms: ichidan).