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A polyhedron is a solid shape with flat faces, not a flat drawing. A box is a polyhedron. A pyramid is a polyhedron. A football made of flat pieces stuck together is a polyhedron too. Each face is a , and those faces meet at edges and corners to make something you could hold. Poly- is 'many'. The second piece comes from an old Greek word for a seat or a base — a face you could sit the solid on — so the whole name is 'many faces'. School talk often says 'sides' for those faces (a cube has six sides); in careful maths the flat pieces are faces, and the lines where they meet are edges. Though actually, this is the pair students mix up for years: a sits flat on the page; a polyhedron has thickness. A triangle drawn in a notebook is not a polyhedron. A paper triangle folded into a closed 3D shape can be. also have extra rules (faces should be flat and fit without gaps), and art or computers sometimes play loose with that. For school, keep the simple contrast: = flat; polyhedron = solid with flat faces.
多面體
組成poly- ('many') + -hedron, from Greek hédra 'seat' (a face of a solid). From New Latin polyedron, from Greek polúedros 'having many seats'.
同家族的字
- polygonsame poly-; the flat shape that makes each face
- tetrahedronsame -hedron: a solid with four faces
- octahedronsame -hedron: a solid with eight faces
原始詞典資料3 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
polyhedronnoun/ˌpɒlɪˈhiːdɹən/
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geometrymathematicssciencesA solid figure with many flat faces and straight edges.
- Of the convex polyhedra with regular faces, the only ones that have tetrahedral, octahedral, or icosahedral symmetry are the Platonic and Archimedean solids.
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engineeringnatural-sciencesopticsA polyscope, or multiplying glass.
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biologybotanynatural-sciencesA stage in the growth of Hydrodictyon, when the resting spore breaks up into several megazoospores that put out horn-like appendages; these polyhedra break up into zoospores.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。