single

1. Origins, structure, and basic meaning

• Structure: 単 conveys being single or not layered; its on-reading is たん.
• Basic usage: 簡単 means simple or easy, while 単語 names a word as a unit of language.

2. Common pitfalls and similar expressions

• 単語 and character count
  • 単語 means a word, not one written character. A word can be written with several characters.
• The role of 簡単に
  • 簡単に済ませる describes handling something simply; 簡単に組み立てられる means that it is easy to assemble. Context distinguishes a simple manner from a low level of difficulty.