Here's why:
* Concrete nouns refer to things that can be physically touched or perceived by the senses. Examples include: table, cat, tree, water, etc.
* Abstract nouns refer to concepts, qualities, or ideas that cannot be physically touched. Examples include: love, happiness, freedom, courage, etc.
"Ella" is a proper noun that refers to a specific person. While people are physical beings, the name itself represents a label or a concept, not the physical person. Therefore, "Ella" falls under the category of abstract nouns.