Why is the ninth month called September?
"jaw, jawbone," 1670s, from Latin maxilla "upper jaw," diminutive of mala "jaw, cheekbone." "Maxilla stands to mala as axilla, 'armpit,' stands to ala 'wing'" [Klein]. Related: Maxillar; maxilliform.
maxilla max·il·la (māk-sĭl'ə)
n. pl. max·il·las or max·il·lae (māk-sĭl'ē)
Either of a pair of irregularly shaped bones of the skull, fusing in the midline, supporting the upper teeth, and forming part of the eye sockets, hard palate, and nasal cavity; upper jaw.