Which of these words is an abstract noun father pink flower snow?

The Word father is an abstract noun as a Word for any male parent, a Word for a concept.

The Word father is a concrete noun as a Word for a specific person.

A concrete noun is a Word for something that can be experienced by any of the five physical senses; something that can be seen, heard, smelled, tasted, or touched.

The nouns pink, flower, and snow are all concrete nouns.