The evolution of ferroelectric domains inside a single grain of a polycrystalline BaTiO(3) ceramic was investigated under quasistatic heating by using polychromatic scanning x-ray microdiffraction. Four domain orientations were observed, three of which exhibited a classic of similar to 90 degrees ferroelastic relationship. The fourth domain orientation was found to be crystallographically related with one of the other orientations by a rotation of either 180.47 degrees or 0.47 degrees. While heating the polycrystalline BaTiO(3) from room temperature to above the Curie temperature (125 degrees C), all four ferroelectric domain orientations rotated toward a paraelectric cubic orientation which was found to be at an intermediate orientation relative to the four domain orientations. The crystallographic relationships of the domains with respect to paraelectric phase were explained using a domain structure model by Nepochatenko.