What words define the word is?

It's tricky to define "is" with other words because it's a fundamental part of language, a core concept. But here are some words that relate to the meaning of "is":

* Equivalence: This is the closest concept to "is." It means "being the same as." "The cat is black" implies the cat is equivalent to the concept of being black.

* Identity: This refers to the fact that something is itself and not something else. "The cat is a cat" expresses its inherent identity.

* Existence: This refers to something being real and having a place in the world. "The cat is" implies the cat exists.

* State of being: "Is" often describes a state of being, like "The cat is asleep."

* Predicates: In grammar, "is" often connects a subject to a predicate (the part of the sentence that describes the subject).

* Linking verb: This is the grammatical function of "is," connecting the subject to the rest of the sentence.

While these words relate to "is," they don't fully capture its meaning. "Is" is more than just a word; it's a fundamental tool we use to understand and express reality.