Physical Hitrate is what physical damage dealing classes use.
It whats make u hit more and miss less on ur targets, the bigger the number the better.
Long range classes have long range hit rate while close range have close range hit rate and it also applies to magical classes but they use magic hit rate.
The higher lvl u go the more u want to have atleast if u like Pvp, in Pve its also good to have some HR on ur accessories.
I bet others can explain it deeper. But for now i say Hr makes the difference if u hit or miss more on ur target.
And with how fast ur attack, thats attack speed. Check ur T window menu to see ur stats.
And might be some good info here; http://lastchaosinfo.wetpaint.com/