- administrative boundary
- administrative division
- adamic earth
- adapter
- adapting piece
- add arrow
- add instruction
- add overlay
- additional
- additional compaction
- additional load
- additional materials
- additive polymerization
- address
- address format
- addressable
- addressed modifier
- addressed retrieval
- addressing
- addressing mode
- adduction
- adequate
- adhesion
- adhesion stress
- adhesive
- adhesive joint
- adhesive property
- adhesive strength
- adhesiveness
- adiabatic
- adiathermany
- adit driving
- adjacent
- adjacent area
- adjacent channel
- adjacent lane
- adjacent point
- adjacent window
- adjective
- adjoining building
- adjoining lift
- adjoining room
- adjoining street
- adjudication
- adjustable joint
- adjustable reamer
- adjustable spanner
- adjuster
- adjustment
- adjustment operation
- administrative map
- administrative quarter
- administrative zone
- administrator
- admiral
- admire
- admissible stress
- admission
- admittance
- admix
- admixture
- admonish
- adobe
- adobe brick
- adobe flooring
- adobe soil
- adopt
- adorn
- adsorbent
- adsorber
- adsorbing clay
- adsorption
- adulterate
- adulterated
- advance
- advance account
- advance timbering
- advanced heading
- advancing mining
- advancing stress
- advantage
- adventure
- adventure playground
- adversary force
- adverse effect
- adverse possession
- adverse slope
- advertising board
- advertising panel
- advice note
- aeolian erosion
- aerarium area
- aerated cement
- aerated mortar
- aerated roof
- aerated spillway
- aeration
- aeration clerestory
- aeration skylight
- aeration system