表面

1. Origins, structure, and basic meaning

• Structure: 表面 is read as ひょうめん and is a noun for the outermost surface of an object or, figuratively, its outward appearance as opposed to what is inside.
• Basic usage: Polishing the surface of a board appears in 板の表面を磨く, while saying that the surface alone is not enough appears in 表面だけでは分からない.

2. Common pitfalls and similar expressions

• Distinction from 中身
  • 表面 refers to an outer surface or outward appearance, whereas 中身 refers to the contents or substance inside.