Here are definitions for some common, and uncommon japanese terms, and their japanese characters, used in the Iaido world.

Aikidō ( 合気道 )
Way of Harmony with the Universe
Budō ( 武道 )
Way of the Martial (-arts)
Bugei ( 武芸 )
Martial Art
Bugeisha ( 武芸者 )
Martial Artist
Chūden ( 中伝 )
The middle tradition/transmission
Dan-to-kyu ( 段と級 )
The system used as a standard to evaluate skills in many Budo. Dan was first used in Kodokan Judo, and the first Shodan (1-dan) was issued in 1883.
Dō ( 道 )
A path, i.e. a path to follow through life. Also philosophy or lifestyle.
Fudōshin ( 不動心 )
Unmovable Mind, i.e. a state of mind that is not disturbed by external forces.
Hanshi ( 範士 )
The highest rank of the three levels of shôgô. Hanshi is awarded to Kyoshi holding 8-dan or above, especially ones who have a noble moral character, thorough knowledge of the principles of Do, and a fully developed technique, and who is at least 55 years of age.
Iaidō ( 居合道 )
Way of Preparedness
Jōdō ( 杖道 )
Way of the Staff
Jutsu ( 術 )
Technique. Also Art.
Kata ( 型 )
Movement pattern, standard form of movement.
Katana ( 刀 )
A Japanese Sword
Kendō ( 剣道 )
Way of the Sword
Kenshō ( 見性 )
Seeing ones nature, a term for enlightenment experiences.
Kihaku ( 気迫 )
Spirit, backbone, mental strength to face any hardship. Also called Kigai. The spirit of fighting back against an attacking opponent.
Kuden ( 口伝 )
Oral tradition/transmission
Kyōshi ( 教士 )
The middle rank of the three levels of Sh&3333;gō. In the ZNKR the recipient must be a Renshi holding 7-dan or above and who has the ability to lead and instruct.
Ma-ai ( 間合 )
Intervall or distance between two opponents. Also including mental distance.
Metsuke
Mushin ( 無心 )
No-mindedness, i.e. a state of mind that is open to everything, fluid and devoid of pre-conceived notions, typically about an opponents impending attack.
Omote ( 表 )
Surface, Front, Right side, Face, Exterior, Outside
Okuden ( 奥伝 )
Qigong
Renshi ( 錬士 )
The lowest rank of the three levels of shôgô. The recipient must have 6-dan and posess the ability to referee.
Satori ( 悟り )
Comprehension, Understanding, Buddhist enlightenment
Seme ( 攻め )
Attack or pressuring the opponent.
Shoden ( 初伝 )
Shōgō ( 称号 )
A title which indicates a certain status or qualification. Within the ZNKR, there are three levels of shogo: Renshi, Kyōshi, and Hanshi.
Ura ( 裏 )
Inside, Palm, Undersurface, Opposite, Wrong side
Zanshin ( 残心 )
Remaining Mind, i.e. a state of mental awareness and relaxed alertness. Often implied by the posture taken after having performed a technique.
Zazen ( 座禅 )
(Zen) meditaion
Zen ( 禅 )
Zen (Buddhism)