What word does Thomas introduce as a “title” for them?

B. Artiists

"Artist?" Thomas suggested. "That's a word. I've never heard anyone say it, but I've read it in some of the books. It means, well, someone who is able to make something beautiful. Would that be the word?"
"Yes, I guess it would. The tyke makes her singing, and it is beautiful."
"When she isn't crying," Thomas pointed out.
"So we are each artists, and we were each orphaned, and they brought us each here. I wonder why. Also, Thomas, there's something else. Something strange."