疾病

1. Origins, structure, and basic meaning

• Structure: 疾病 (しっぺい) is a formal noun for a disease or illness affecting physical or mental function.
• Basic usage: It appears in lectures and materials that examine disease-related factors or classifications.
  • 講義では季節と疾病の関係を扱った。 — The lecture covered the relationship between seasons and disease.
  • 資料に主な疾病の分類が示されている。 — The material presents a classification of major illnesses.

2. Common pitfalls and similar expressions

• Formal and everyday terms for illness
  • 疾病 is formal and common in academic or institutional contexts, while 病気 is the broader everyday word for illness or being sick.