Abstract, Concrete, General and Specific Terms
This page was written by John Friedlander, associate professor in the English department at Southwest Tennessee Community College. It is used here with his permission.
The link address is: http://guidetogrammar.org/grammar/composition/abstract.htm#:%7E:text=Concrete%20terms%20refer%20to%20objects,%2C%20green%2C%20hot%2C%20walking.