/saJjJA / सञ्ज्ञा

A /saJjJA is a word that is used as a label for some particular sort of thing, even though the "proper" meaning of the word, that comes from its parts, is more general.

Example. The descriptive tAmrakeza- ताम्रकेशॱ, according to grammar, may be used to describe anyone or anything that has copperlike hair. But if you use the word as a nickname for your redhead friend, then it is a tag. Because you are using it in a narrower sense.

All proper names (nouns that mean a particular individual) are tags, but not all tags are proper names. A word like **kRSNazakuni- कृष्णशकुनिॱ is not a proper name, but it is considered to be a tag when it means "crow", that is, when it pinpoints a particular sort or bird. In its regular meaning of "(place) in which there are black birds", it is not a tag.

Of course, if your pet crow is called "Polly", that's also a tag, in addition to being a proper name.

Sanskrit grammar allows some /taddhita to be added and some compounds to be formed only when the sense is a tag. So rule adUrabhavazca allows you to rename Memphis (or any other particular area near the misisipi मिसिसिपि) as maisisipam मैसिसिपम्, even though the word maisisipam मैसिसिपम् is not allowed to mean "an area near the misisipi मिसिसिपि" in general.