The term aikido (kanji: 合気道) means "way of gathering energy" in English. It is written あいきどう in hiragana. It may also be rendered in English as aikidō or aikidou. It's pronounced roughly like "eye-key-doe".
The term for this martial art brings together the two kanjis for meeting and energy. 合, in the Chinese reading, is go and is used in words like gathering (集合, shugo), fusion (融合, yugo), and synthetic (合成, gosei). In verb form (the infinitive being au, 合う), it only refers to the meeting of impersonal forces.
気 is widely used both in isolation and in conjunction with other kanji. For example, to end a sentence with 気がする (ki ga suru, literally “there is a mood/atmosphere/feeling”) is equivalent to saying in English, “I have a feeling that…” As a side note, 気 is a simplified form of the Chinese character for qi (“chee”), often translated as “life force.”