Foo is both the first and fifth item - Foo is the first item in that segment (or slice if you're a weird golang programmer) but it is also the fifth item in some sir-not-appears-in-this-film list that is responsible for the odd numbering. If I said "I just finished the fifth item on our todo list" you'd mark off Foo because that's clearly what I was referring to.

Places can have two labels (or more!) and, for bonus points, zeroth is a thing because we both know what that word means.