It's an indefinite article.
I've seen no examples online which say that "A" is not a world.
e.g. :
"The words A and AN are called "indefinite articles" and apply to some non-specific member of a group.
Use "an" when the following word starts with a vowel sound. (Some users will use "an" before words beginning with "his-" if the user pronounces it with the soft sibilant instead of a hard H, e.g. "an historic occasion")
so take one of your words off
