AHD or Ahd may refer to:

  • Audio High Density, an audio-only version of the Video High Density videodisc format
  • Acoustic Hailing Device, an audio device capable of providing high acoustic output at significant distance
  • Australian Height Datum, a geodetic datum for altitude measurement in Australia
  • National Rail Station Code AHD: Ashtead railway station, Ashtead, Surrey, England
  • Anthony Henday Drive, an expressway in Edmonton, Alberta

In linguistics:

  • Althochdeutsch (Ahd.), the German name for Old High German, the earliest stage of the German language
  • The American Heritage Dictionary of the English Language

In medicine:

  • Advance Health Directive, an Australian legal document
  • Alveolar hydatid disease, a parasitic disease