| infection | 感染 |
| inhibition | 抑制 |
| injection | 注射 |
| inscription | 刻むこと |
| inspection | 検査 |
| institution | 制度 |
| instruction | 教育 |
| intention | 意図 |
| interaction | 相互作用 |
| interception | 横取り |
| interruption | 中断 |
| intersection | 交差 |
| intervention | 介入 |
| introduction | 紹介 |
| intuition | 直観 |
| invention | 発明 |
| junction | 結合 |
| jurisdiction | 司法権 |
| lotion | 化粧水 |
| mention | 言及、言及する |
| misconception | 誤解 |
| motion | 動き |
| notion | 観念 |
| nutrition | 栄養摂取 |
| objection | 反対 |
| obstruction | 障害 |
| opposition | 反対 |
| option | 選択 |
| partition | 分配 |
| perception | 知覚 |
| perfection | 完全 |
| persecution | 迫害 |
| petition | 請願 |
| pollution | 汚染 |
| portion | 部分 |
| position | 位置 |
| precaution | 用心 |
| prediction | 予言 |
| premonition | 予感 |
| preposition | 前置詞 |
| prescription | 処方箋(せん) |
| presumption | 推定 |
| prevention | 予防 |
| production | 生産 |
| prohibition | 禁止 |
| projection | 投射 |
| promotion | 昇進 |
| proportion | 割合 |
| proposition | 提案 |
| prosecution | 起訴 |
語尾が「-tion」で終わる英単語一覧
