What does the word link mean?

Usage examples for link

  1. The link would be hard to break- even if he wanted to. – Beyond by John Galsworthy
  2. The link was broken; her words had called him from the sphere of the beautiful stranger, and he needed rest. – Dawn by Mrs. Harriet A. Adams
  3. It never occurred to me at the moment however to connect the two, in spite of the link of swan's- down. – The Enchanted Typewriter by John Kendrick Bangs