The name is two words. 合気 (aiki) is the joining of ki, and 道 (dō) is the way. It is the suffix by which a Japanese art declares itself a path rather than a set of techniques, as 柔道 and 剣道 do. The dictionaries define aikido by its descent from the Daitō-ryū and by its pins and throws. The art's own books define it as harmony with ki, the founder's sense of aiki. The two do not conflict: one says what the art is, the other what he meant by calling it that.
Aiki carries three senses, in order of age. The oldest is the deadlock of two matched fighters, which the Edo sword schools taught a swordsman to break. The next is the Meiji technique of seizing an opponent's ki before the swords cross. The youngest is Ueshiba's joining of one's own ki with the ki of the universe. A reader who takes the word for harmony alone has the youngest of them.
Nine of the ten designs write 合氣道 with the older form of the character ki. The Aikikai's own newspaper has carried that form in its title since 1959. The tenth design writes the modern form, 気; they are one word.
合気道 is composed of the kanji 合 (read ai) meaning "join; meet", 気 (read ki) meaning "air, breath, spirit", and 道 (read dō) meaning "the way".
Ueshiba Morihei gave his art the name 合気道 in February 1942, on his son's account, when it entered the Dai-Nippon Butokukai after twenty years under the names aiki-jūjutsu, aiki-jutsu and aiki-budō; the word aiki itself is older than the art and was not his.
We want you to be as happy with the meaning as you are with Master Takase's art. To learn more, visit Philology of 合氣道.