Define options in input

I am trying to figure out how to define options in preferences. I want to assign one or two letter abbreviations to later use in the smartapp. How do I go about doing this?

section("Significances") {
    input(name: "sigs", type: "enum", title: "Significance Types", multiple: true, options: ["Warning","Watch","Advisory","Statement","Forecast","Outlook","Synopsis"])
        }