The story
Borrowed from Japanese 合(あい)気(き)道(どう) (aikidō, “aikido”, literally “way of adapting the spirit”), from 合(あい) (ai, “together, unify”) + 気(き) (ki, “spirit; breath”) + 道(どう) (dō, “way”). Doublet of hapkido.
Etymology from Wiktionary, CC BY-SA 4.0.