Kalmar "Caddo" tana nufin ƙungiyar 'yan asalin ƙasar Amirka waɗanda tarihi ya kasance a kudancin Great Plains yankin Arewacin Amirka, musamman a yankin da ke gabashin Texas, yammacin Louisiana, da kudu maso yammacin Arkansas. Mutanen Caddo an san su da hadaddun al'ummomi, noma, da hanyoyin sadarwar kasuwanci. Kalmar "Caddo" kuma tana iya nufin yaren Caddo, wanda har yanzu wasu membobin Caddo Nation ke magana a yau.