英語「plane」の意味・使い方・読み方 | Weblio英和辞書 From Latin pl ā num (“ flat surface ”), a noun use of the neuter of pl ā nus (“ plain ”) The word was introduced in the 17th century to distinguish the geometrical senses from the other senses of plain
英語「plainly」の意味・使い方・読み方 | Weblio英和辞書 副詞 plainly (comparative plainlier or more plainly, superlative plainliest or most plainly) In a plain manner; simply; basically She decorated the room plainly but neatly