* Thunder: Not an abstract noun. Thunder is a concrete noun because it's a sound we can hear, and therefore, experience with our senses.
* Rain: Not an abstract noun. Rain is a concrete noun. We can see it, feel it, and even taste it.
* Lightning: Not an abstract noun. Lightning is a concrete noun. It's a visual phenomenon we can see and experience.
Abstract nouns represent things that we cannot experience with our five senses (sight, sound, smell, taste, touch). Examples include:
* Love
* Happiness
* Freedom
* Justice
* Beauty
Let me know if you have any other nouns you'd like classified!