Jicama
From SUALEX
The word jícama "Pachyrhizus erosus" (First attested in 1604 (Haugen 2009)) comes from Nahuatl <xicamatl> /ʃikama-tl/ which is in turn composed of two PSUA roots xi- "skin, husk, peel" and *kama "sweet tuber, camote" (the Nahuatl word camohtli "sweet potato" comes from the same root, but this can be reconstructed as PSUA *kamawi). The compound ʃi-kama is not attested outside of Nahuan, and can be reconstructed only for proto-Nahuatl.