
Audio Codec 3. This was the original and more technical name for Dolby Digital. Replaced by marketing mavens when they realized that Dolby's name was not in the title. Some RF modulated, 5.1-encoded laser discs were labeled as AC3. Later versions were labeled as Dolby Digital.
Found on
http://www.encyclo.co.uk/local/21058

In hypoeutectoid steel, the temperature at which transformation of ferrite into austenite is completed upon heating.
Found on
https://steelforge.com/literature/steelog-the-5000-word-metals-glossary/
No exact match found.