Aikido (合気道 Aikidō^?) is a Japanese martial art developed by Morihei Ueshiba as a synthesis of his martial studies, philosophy, and religious beliefs. Aikido is often translated as "the Way of unifying (with) life energy or as "the Way of harmonious spirit." Ueshiba's goal was to create an art that practitioners could use to defend themselves while also protecting their attacker from injury

Aikido is performed by blending with the motion of the attacker and redirecting the force of the attack rather than opposing it head-on. This requires very little physical strength, as the aikidoka (aikido practitioner) "leads" the attacker's momentum using entering and turning movements. The techniques are completed with various throws o joint locks.

Aikido derives mainly from the martial art of Daito-ryu Aiki-Jujitsu, but began to diverge from it in the late 1920s, partly due to Ueshiba's involvement with the Omoto-kyo religion. Ueshiba's early students' documents bear the term aiki-jūjutsu.

Ueshiba's senior students have different approaches to aikido, depending partly on when they studied with him. Today aikido is found all over the world in a number of styles, with broad ranges of interpretation and emphasis. However, they all share techniques learned from Ueshiba and most have concern for the well-being of the attacker.

    合 – ai – joining, unifying, combining, fit
    気 – ki – spirit, energy, mood, morale
    道 – dō – way, path

The term "aiki" does not readily appear in the Japanese language outside the scope of Budo. This has led to many possible interpretations of the word. 合 is mainly used in compounds to mean 'combine, unite, join together, meet', examples being 合同 (combined/united), 合成 (composition), 結合 (unite/combine/join together), 連合 (union/alliance/association), 統合 (combine/unify), and 合意 (mutual agreement). There is an idea of reciprocity, 知り合う (to get to know one another), 話し合い (talk/discussion/negotiation), and 待ち合わせる (meet by appointment).

気 is often used to express a feeling, as in 気がする ('I feel', as in terms of thinking but with less cognitive reasoning), 気持ち (feeling/sensation), and 気分 (mood/morale). It is used to mean energy or force, as in 電気 (electricity) and 磁気 (magnetism).

The term dō connects the practice of aikido with the philosophical concept of Tao, which can be found in martial arts such as judo and kendo[citation needed], and in the more peaceful arts such as Japanese calligraphy (shodō), flower arranging (kadō) and tea ceremony (chadō or sadō).

Therefore, from a purely linguistic point of view, aikido is 'Way of combining forces'. The term aiki refers to the martial arts principle or tactic of blending with an attacker's movements for the purpose of controlling their actions with minimal effort.[6] One applies aiki by understanding the rhythm and intent of the attacker to find the optimal position and timing to apply a counter-technique. This then is very similar to the principles expressed by Jigoro Kano, founder of Judo.