Correction: Equinox is mid-weight and Eden is light-weight
I wear shoe size 8.5 or 9 (USA) so ordered M that said it fit size 7-9.5. The socks were about an inch too long. I exchanged them for size small, and those fit perfectly. However, I see that the new pair is Eden (midweight) instead of Equinox (lightweight) - but I'm OK with that. The socks are cushiony on the bottom and the tops are not too tight around the leg. Very comfortable. Gordini's exchange policy was easy - they emailed me a return shipping label so cost to me was nothing additional. It is interesting to note however, that I ordered a men's large (for sizes 10-12.5) pair of Eden for a person with shoe size 10.5 and they fit perfectly.
So I recommend that Gordini double check their sizing on the Women's socks.