| Kaeshi | 返 し | counter, return | |
| Kaho | 下 方 | lower direction | |
| Kaiten | 回 転 | rotation | |
| Kaitennage | 回 転 投 げ | rotation throw | |
| Kakudai | 拡 大 | expansion | |
| Kamae | 構 え | posture, stance |  |
| Karate | 空 手 | art of the empty hand |  |
| Kata | 形 | form | |
| Kata | 肩 | shoulder | |
| Katameru | 固 め る | hold, fix | |
| Katana | 刀 | Japanese sword | |
| Katana o nuku | 刀 を 抜 く | unsheathe a sword | |
| Katana o sasu | 刀 を 挿 す | Sheathe a sword | |
| Katate | 片 手 | one hand | |
| Katatekosatori | 片 手 交 叉 取 り | take hold of one hand cross-over | |
| Katatetori | 片 手 取 り | grab one hand | |
| Katatori | 肩 取 り | shoulder grip | |
| Keikogi | 稽 古 着 | training dress, white trousers, jacket and belt | |
| Ken | 剣 | sword | |
| Ken | 拳 | fist | |
| Kenbu | 剣 舞 | sword dance | |
| Kendo | 剣 道 | Way of the sword | |
| Kengi | 剣 技 | sword art | |
| Kenko | 健 康 | health | |
| Kenkodo | 健 康 道 | way of health | |
| Kenkotaiso | 健 康 体 操 | health exercises | |
| Kesa | 袈 裟 | across the chest | |
| Ki no Kenkyukai | 気 の 研 究 会 | "Association for the research of Ki" | |
| Kiai | 氣 合 | short yell before or during a strike or technique | |
| Kiri | 切 り | cut | |
| Kiribarai | 切 り 払 い | cutting in a sweeping motion | |
| Kirikaeshi | 切 り 返 し | counter cut | |
| Kitei | 規 定 | established standard | |
| Kohai | 後 輩 | junior student | |
| Koho | 後 方 | to the back | |
| Kokoro | 心 | heart, mind, spirit | |
| Kokyu | 呼 吸 | breathing |  |
| Kokyu-Dosa | 呼 吸 動 作 | sitting practice with partner holding with Ryotetori | |
| Kokyuho | 呼 吸 法 | breathing method | |
| Kokyunage | 呼 吸 投 げ | Breath throw | |
| Kosa | 交 差 | across | |
| Kosatori | 交 叉 取 り | cross-over grip | |
| Koshi | 腰 | Hip | |
| Koshin | 後 進 | backwards | |
| Koshinwaza | 後 進 技 | exercise of going backwards | |
| Kote | 小 手 | forearm | |
| Kotegaeshi | 小 手 返 し | turn wrist back | |
| Koteoroshi | 小 手 下 ろ し | take forearm down | |
| Kubi | 首 | neck | |
| Kubishime | 首 締 め | Choke | |
| Kumi | 組 み | group, set | |
| Kumitachi | 組 太 刀 | sword practice in a couple | |
| Kumiwaza | 組 み 技 | practice in a couple | |
| Kyu | 級 | Student grade, white belt | |
| Kyu | 九 | nine | |
| Kyudo | 弓 道 | the way of the bow | |
| Kyukyu | 九 級 | 9. Kyu | |