紫外線

1. Origins, structure, and basic meaning

• Structure: 紫外線 is read as しがいせん and is a noun for ultraviolet rays or UV light.
• Basic usage: Protection from UV appears in 紫外線から目を守る, while blocking its passage appears in 紫外線を通しにくい.

2. Common pitfalls and similar expressions

• から and を
  • 紫外線から marks the harmful source from which something is protected, while 紫外線を marks what is prevented from passing through.
• Difference from 日光
  • 日光 means sunlight as a whole, whereas 紫外線 identifies ultraviolet light in particular.