Adherence. The extent to which a coating bonds to a substrate.

Adherence index. Measure of the adherence of porcelain enamel and ceramic coatings to sheet metal. (ASTM C-313).

Alpha Rockwell hardness. Index of the resistance of a plastic to surface penetration by a specified indentor under specified load applied with a Rockwell hardness tester. Higher values indicate higher indentation hardness. (ASTM D-786).

Annealing point. Temperature at which internal stress in glass is substantially relieved in 15 min. (ASTM C-336).

ASTM hardness number. Depth (in thousandths of an inch) of penetration of an indentor into a rubber specimen under loads and conditions specified in ASTM D-314. While suitable for most common grades of rubber, ASTM hardness number is not applicable to extremely hard or soft rubbers.