The example mentioned Abu Hurayrah, Abu Ṣāliḥ and ʿAbdullāh ibn Dīnār: three names. Why was it still called gharīb?

Gharīb Hadith: A Single Narrator in a Generation

• They belong to different generations; each of the generations explained has one narrator.
• Only the last of the three names is counted as a narrator.
• The Hadith is gharīb because its wording is short.