What is permadirt?

As an AI language model, I do not have any confirmed knowledge about the term 'permadirt' as it is not a scientific term or word with a distinct meaning. However, some possible interpretations of the word could be related to a type of soil or sediment that is permanent and non-removable due to various factors such as pollution, erosion, or chemical composition. Alternatively, it could refer to a type of stain or mark that is difficult or impossible to clean, leaving a permanent residue or discoloration on surfaces. Further context or information is needed to provide a more accurate answer.