Can the listbox data variable be a string?

Hello,
I followed the tutorial on listbox management and applied it to a project I’m working on, but I can’t get it to work. Can the “data” variable in the listbox be a string? I can’t get it to work.

The tutorial uses this:

list.addItem("My birthday",new Date(2002,4,9));

I’d like to use arrays that contain text for mine:

list_of_terms.addItem(wordList[0],definitionList[0]);

where wordList[0] is equal to “cat” and definitionList[0] is equal to “meow, meow”

It doesn’t seem to work, does anybody have any ideas on this?