to even things that are flat, such as boards or the ground
IPAspelling:
semiːʃtiɑ
Alonso de Molina:
cemixtia. nitla. (pret. onitlacemixti.) ygualar cosas llanas, como tablas, o suelo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 16r. col. 2. Thanks to Joe Campbell for providing the transcription.