Acorn's coat is an outer protective layer that covers the acorn nut. There are several synonyms for acorn's coat including acorn husk, acorn shell, and acorn cap. The acorn husk is the fibrous outer layer that surrounds the acorn nut and protects it from environmental factors. The acorn shell is the hard, woody covering that protects the nut from predators and damage. The acorn cap is the top part of the acorn shell that covers the nut and is often used in crafts and decorations. Overall, these synonyms refer to the various layers that protect the acorn and allow it to survive and grow into a majestic oak tree.