I have a theory but I can’t figure out what it means.
Have you noticed that the titles of The Hunger Games trilogy go from three words, to two words, to one word?
The Hunger Games
I like to think that it has something to do with Katniss and Gale getting together. Perhaps the first title represents Katniss, Gale, and Peeta all being separate, but aware, of each other, Catching Fire represents that only one can be with Katniss (we all know that’s Gale), and Mockingjay represents that only Gale survives (note the ‘g’ and ‘a’ in the word mockingjay).
I know. I’m stretching.