Component (a building block) — not the same thing as a radical or a sound component. · 5strokes
初补衫衬袄袍袖袜
Kangxi radical no.145 · 衣 · 6strokes — 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.
衣表衫衬衰衷袁袄