Temperature indicating sign or label.

"Термознак" is a some kind of termo label /thermal sensor . It is often used on the packages of different products to indicate temperature of the product. For example, on the bottle of beer there might be a small spot or label of particular color and the color of this label could change depending on whether the bottle is cold or warm.

Термознак is a sign (for example, a sign on the road - http://termoznak.pl/wp-content/uploads/2015/02/%D0%A2%D0%95%D0%A0%D0%9C%D0%9E%D0%97%D0%9D%D0%90%D0%9A-%D0%91%D0%B5%D0%B7%D0%BE%D0%BF%D0%B0%D1%81%D0%BD%D0%B0%D1%8F-%D0%B4%D0%BE%D1%80%D0%BE%D0%B3%D0%B0-%D0%B2-%D1%88%D0%BA%D0%BE%D0%BB%D1%83-%D0%BD%D0%BE%D0%B2.pdf) which made from the stable material. So it is really hard to erase it or spoil.

thermo = термо sign = знак Need context. But maybe it is special sign, for example, color and change when temperature low.

Thanks KP :)