a key; or, an opener 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), 238.
literally, enameled ground, but probably referring to a type of pavement (see Molina), apparently smooth and flat like the gold pieces prepared for tribute payment in the expresssion "coztic teocuitla tlatemantli," below (SW)