The word "another" is used to refer to an additional one of the same kind or a different one. It indicates that there is an extra item or person besides the one already mentioned or being referred to. For example, if you have one apple and you want one more, you would say you want "another apple."
The word "another" comes from the Old English "anōther," which is a combination of "an" (meaning "one") and "ōther" (meaning "other"). The structure indicates the idea of something being different or additional compared to the first.