厚紙

1. Origins, structure, and basic meaning

• Structure: The written form is 厚紙, read あつがみ. Elements for thickness and paper combine to denote paper thick enough to hold its shape.
• Basic usage: 厚紙を切る describes cutting the material for a stand, while 厚紙を入れる describes inserting it in an envelope to protect documents.

2. Common pitfalls and similar expressions

• Material for a picture-frame stand
  • Heavy paper or cardboard is cut into a stand for a picture frame. Example: 厚紙を切って写真立ての台を作った。 — I cut cardboard to make a stand for the picture frame.
• A stiffener protecting documents
  • Thick paper inside the envelope protects the enclosed documents. Example: 封筒の中に厚紙を入れて書類を守った。 — I placed thick paper inside the envelope to protect the documents.