People have different ideas of "thick" but there I'm sure there is one basic, mutual meaning of the term.
Thick basically means a healthy, high amount of fat in all the right places of a women's body, which is her buttocks, hips, thighs, and breasts, along with a comparatively small waist. Now some people will consider a women thick if one or more body part(s) has a high amount of fat in them. But for me, atleast the butt, hips, and thighs must be contain a lot of fat and a comparatively small waist present to be considered "thick". And I in my opinion this is how it should be. I also find wide ankles(not cankles), and large calves very attractive on thick women. Also, I also like very thick type, the ones who many may consider fat. But as long as most of the fat/thickness is in the right places, its perfect to me.
Being thick is often attributed to black women, who are can be commonly seen with large, and in my opinion very sexy, bodies. And most people would like to call it a very ignorant assumption, but if they do some research on genetics, and ancient Africa, they'd find that its very much true. But of course this doesnt mean they can't really skinny either. But it is ignorant to say that white women or asian women can't be thick or something on those lines. I've seen thick women in all ethnic groups and most others have too.
I was just want to say this now, Beyonce is in deed not thick!