ANOTHER comes from the combination AN +
OTHER, so ANOTHER will be used in those cases where we would use A/AN, that is,
before singular countable nouns.
For example, “Would you like a glass of water?” ---- “Would you like
another glass of water?”
On the contrary, OTHER will be used in
those cases where we wouldn’t use A/AN, that is, with the definite article
THE, a possessive adjective (my, your, his …), SOME or ANY; or any plural
countable or uncountable noun.
Some instances: “I left my wallet in my
other trousers”; “Are you free any other day of the week?”
