AHPronunciation: /eɪˈeɪtʃ/Definition of AH abbreviation in the year of the Hegira (used in the Muslim calendar for reckoning years from Muhammad’s departure from Mecca in ad 622); of the Muslim era:a Koran dated 556 ahOrigin:from Latin anno HegiraeAH in other Oxford dictionaries Definition of AH in the US English dictionary