Spider in Italian; there is no "y" in the Italian alphabet. It's a body type more than a model name, deriving from a type of light, nimble horse-drawn coach. The Graduate was a trim level during part of the '80s, the lowest of three levels, the other two being Veloce and Quadrifoglio. Normally with Alfa, a Quadrifoglio badge indicates a higher performance level as well, but with the Spider, the levels were purely the amount of creature comforts that were installed;the powertrain remained the same. Higher levels had better carpeting and upholstery, electric instead of manual windows, air conditioning, etc. The Quad also came with a removeable hard top. So ironically, the Graduate, with fewer accessories making demands of the engine, and being a little lighter, would perform better.
In 1971, when my car was made, there was just one level, Veloce. The car has rubber mats and no carpeting (I believe they viewed the inside as an extension of the outside with the assumption that it will get wet). No air conditioning. 1971 was a transitional year, being the last year of the 1750 engine, and the first year of the Kamm tail design. Some prefer the 1750 over the two-liter, as it's a bit more willing to rev.