| O: | “Big” or “great.” | |
| Obi: | Belt. | |
| Obi-otoshi | Belt drop | |
| Odachi:: | See “tachi.” | |
| O-goshi: | Major hip, hip technique | |
| O-guruma: | Major wheel. Judo foot technique. | |
| Oi-zuki | Step punch. | |
| Okuri-ashi-harai: | sending foot sweep, Judo foot technique. | |
| Omote: | “Front” or “obvious.” | |
| Oni ken: | Extended knuckle fist. | |
| Orei: | “Respect” or “etiquitte.” A expression of formal greeting in karate. | |
| Orun: | Right. | |
| Osae-komi-waza: | Hold down techniques. | |
| Osu: | a combination of two different kanji (Sino-Japanese characters). The verb ‘osu’ means to push shove, press, squash, compress or stamp, and ‘shinobu’ or “Nin” means “to bear, endure, resist, or put up with or to hide. | |
| O sensei: | “Great teacher.” The honorific prefix “o” attached the word sensei indicates respect and acknowledgement of the chief instructor of a system. Most commonly associated with Uyeshiba Morihei, founder of modern day Aikido. | |
| O-soto-gaeshi: | Major outer counter. Judo foot technique. | |
| O-soto-guruma: | Major outer wheel. Judo foot technique. | |
| O-soto-otoshi: | Major outer drop. Judo foot technique. | |
| Otoshi: | Drop. | |
| O-uchi-gaeshi: | Major inner counter. Judo foot technique. | |
| O-soto-gari: | Major outer reap. Judo foot technique. | |
| O-uchi-gari: | Major inner reap. Judo foot technique. |
