What does High Brief mean? Which part is high?

The waistband sits higher on your torso than typical brief panties do. I’m 5’ 7” and my hips are about 52” around at the moment, so I ordered these in a size 11 and the waist sits directly over my belly button. I have a rather long torso, so on an average woman these would probably sit higher, likely right at the natural waist, which is usually slightly above your belly button. I’d probably steer clear of these if you have a short torso though, as I believe they may sit just under your bra band/breasts in that case. All other mainstream brief panties (like Fruit of the Loom, Hanes, and their respective plus size brands) sit lower, typically below the belly button on women with an average torso.

They are made in Thailand -- the last package I bought of these did not last 3 months when they started to come apart at the leg and waist bands. I would suggest trying "Fit For Me" by Fruit of the Loom instead.

It says 100% cotton but then also says solids/prints: 100% cotton; heathers: 75% cotton/25% polyester. what is heathers?

The only heathers I am aware of are the grey ones and they are not 100% cotton. The others are 100% cotton and I don’t notice any difference in comfort between the grey ones and the others. I hope this helps.