thick = size dense = number of pieces per block If something is denser than water, it sinks. If something is less dense than water, it floats. That is the meaning of "dense". Google translate gives two different words for "thickness" and "density" (grubość gęstość).

Thick Something that is thick has a large distance between its two opposite sides. example he wore glasses with thick rims. Also you can use thick to talk or ask about how wide or deep something is. like how thick are these walls? Dense Something that is dense contains a lot of things or people in a small area. like its fur is short, dense and silky. In science, a dense substance is very heavy in relation to its volume. like an iron ball is dense compared to a plastic ball

There are two possible interpretations: Thick - heavily built or having a large distance from one side to the other. Dense - having a large weight for unit volume. Somthing can be thick without being dense, and visa versa. There is another interpretation: Thick and dense both are used to mean stupid, not so smart, dim-witted.