Shai-Hulud  (Arabic: شَيْء خُلُود Shayʾ-Khulud)

As with many Fremen terms and words, Shai-Hulud is more than a descriptive term for a physical entity. Specifically, it often alludes to the Fremen belief that the sandworm is a physical embodiment of the One God that created and governs the universe. Thus to the Fremen Shai-Hulud is a sacred term that is usually spoken with a tone of awe, fear, or respect.