What is the difference between indexes and indices?

Indexes and indices are two versions of a plural noun that means an indicator or a list of names. Indexes is also a present tense verb, but indices cannot be used that way. Indexes is probably the better choice for formal writing not related to mathematics. Indices is especially common in technical and formal writing.

Is index a plural?

Both “indexes” and “indices” are correct English plurals of the singular noun “index.” But there is a preference for indices outside North America because of solid adherence to Latin plurals. Indexes or Indices? Plurals of nouns take different rules. Some only need an -s or -es at the end, while others require a change in spelling.

Should I use indexes in my writing?

It’s wise to use “indexes” in your writing as a non-technical plural form or in an informal context. But some books that cater to formal writing settings still prefer “indexes.” Language experts also agree that you should use “indexes” when referring to citation listings, bibliographies, and other written documents.

Is indices a valid English word?

Both are valid English; that is why you see both used. One person may be used to the other, while the guy down the hall says it the other way. See dictionary.com if you haven't already. Also in the Oxford Dictionary of English, something like "plural: "indexes" or "indices" (especially in technical writing)". One isn't more correct than the other.