a piece of writing, a painting, or something with a design (see attestations); the initial "i" on this word drops away before tla-, as in tlacuilolli, which has probably contributed to the evolution of the word cuilolli
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 216.