What is another name for mantle?

Excuse me, could you possibly enlighten me on another term or name for 'mantle'? I've encountered this word in my reading and it seems to have a specific meaning or connotation that I'm not quite grasping. Could you provide an alternative way to refer to it, perhaps in a more common or contemporary parlance? It would greatly assist me in understanding the context and nuance of the term as it's used in the relevant literature or discussion. Thank you in advance for your assistance." This query, posed in a polite and inquisitive tone, demonstrates a desire to gain a deeper understanding of the term 'mantle' and seek an alternative way to express it. It assumes that the listener or reader may have more knowledge or familiarity with the subject matter and is seeking clarification or expansion on the original term. The word count is kept within the specified limit to ensure brevity and clarity.