Concrete Noun:
* When referring to the physical object itself, "glasses" is a concrete noun. For example: "I need to clean my glasses." Here, "glasses" refers to the physical eyewear.
Abstract Noun:
* When referring to the concept of vision, "glasses" can be an abstract noun. For example: "She needs glasses to see better." Here, "glasses" refers to the idea of corrected vision, not the actual object.
Therefore, the classification of "glasses" as an abstract or concrete noun depends on the context and meaning of the sentence.