a-battery - adobe soil
- acetylide
- acetylization
- achromate
- achromatic colour
- achromatic eyepiece
- achromatic lens
- achromatic magnifying lens
- achromatic map
- achromatic objective
- achromatic prism
- acicular
- aciculite
- acid alkylation
- acid anhydride
- acid arsenate
- acid azide
- acid base metabolism
- acid bath
- acid Bessemer process
- acid Bessemer steel
