- admissible, allowable, permissible
- alternating voltage, AC voltage
- alternating current, AC current
- angle gearing, elbow gear
- automatic gain control, AGC
- acoustic storage, acoustic memory
- acoustic receiver, sound receiver
- add-on equipment, additional equipment; applique equipment
- alarm cut-off, ACO
- alarm processing, alarm treatment
- acoustical alarm, audible alarm
- allocation scheme, allocation plan; equipment configuration plan; equipment plan;
- analog display, analog indication
- air conducting sheet, airflow sheet
- assembly appliance, assembly jig
- annual output, annual production
- aligning plug; spigot
- accession country
- acetum
- ACP
- activity holiday
- activity pattern
- advertising supplement
- afterpains
- age difference
- age spot
- agency agreement
- agricultural college
- air bladder
- air fleet
- air miss
- air parcel
- air-raid warning
- air taxi
- airtel
- all-inclusive offer
- allium
- ancylostomiasis
- arbitrational
- arch-rival
- arr.
- artificial limb
- audit department
- autochanger
- autosome
- average adjuster
- axis of symmetry
- assignability
- area of arable land
