Markings on Silver Ring: A&C 375 83

by Lisa Tregenza
(Melbourne, VIC, Australia)

I have this ring, and it may have been my mums and I wanted to know what the markings on the inside of the band mean.
On one side it has 375 in a circle and A&C next to it.
On the other side it has in a circle, the number 83.

I know 375 means 9k, but I wanted to know what the others meant.
Thanks!