What is "Tin"?
Answer from a Native speaker
"Tinned" is an adjective to describe any substance that has been stored in a tin. A tin is exactly the same as a can, except instead of being in a cylindrical shape, it is in a rectangular shape instead. Many types of fish are stored in tins, which is why Gordon Ramsey has used the expression "tinned anchovy." Ex: Tinned fish is affordable and can be stored for a much longer time than fresh fish. Ex: I put one tin of anchovies into the pasta sauce, and it added a lot of flavor.