氏

shì clan; family name

Component (a building block) — not the same thing as a radical or a sound component. · 4strokes

Forms

Characters that use it as a component

纸昏

Characters filed under it as a radical

Kangxi radical no.83 · 4strokes — The 214 Kangxi radicals

Filed under it in a dictionary. That is a lookup convention — it does not mean it is the only part the character is built from.

氏民氓