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 I will be plain with you ― speak plainly ― speak in plain terms ― speak in plain English ― call a spade a spade 発音を聞く 例文帳に追加 露骨に言おう - 斎藤和英大辞典