means a Mexican dish of masa (corn dough) filled with meats, cheeses, or chilies, wrapped in a corn husk or banana leaf and steamed until firm.

from From Mexican Spanish 'tamal,' borrowed from Nahuatl 'tamalli,' the language of the Aztecs. English speakers, seeing the plural 'tamales,' back-formed a singular 'tamale' — so the standard English word is really an Aztec plural that got tugged back into the singular along the way.