- antistatic mat
- antithesis
- antithetic fault
- antithetical
- antithetical events
- antium
- antivibration
- antrum
- antrum maxillare
- anvil
- anvil chisel
- anvil scale
- anvil stake
- anvil stand
- anvil swage
- anxiety
- anything
- apart
- apartment
- apartment unit
- apeak
- apercu
- aperiodic
- aperiodic antenna
- aperiodic galvanometer
- apertura piritormis
- aperture
- aperture aberration
- aperture card
- aperture core
- aperture mask
- apex
- apex angle
- apex block
- apex connector
- apexbeat
- aphelia velocity
- aphelion
- aphorism
- aphyrous clay
- apiary
- apical
- apical angle
- apical wood
- aplanatic lens
- apochromatic lens
- apogee
- apogee point
- apolar
- apolar posteriori
- aponeurositis
- apophorometer
- apophysis
- apostrophe
- apparatus
- apparatus room
- apparent
- apparent brightness
- apparent cohesion
- apparent density
- apparent energy
- apparent power
- apparent resistance
- apparent stress
- apparent thickness
- apparent variable
- appeal
- appear
- appearance
- appearance potential
- append
- appendage
- appendage task
- appendix
- appliance
- appliance computer
- appliance coupler
- appliance panel
- applicable law
- applicable surface
- Applicant
- application
- application field
- application generator
- application icon
- application programmer
- application software
- application study
- application temperature
- applications developer
- applied
- applied chemistry
- applied moment
- appoint
- appreciably
- appreciation
- appriori
- approach
- approach bank
- approach control