Terra cotta is a type of earthenware (as opposed to porcelain and stoneware) that is common but looks distinctly different from most other earthenware.  

Terra cotta is usually a distinct orangish, but sometimes is brown/gray.  As with all earentheware it is not water tight and must be glazed to hold water.  Only unglazed stoneware holds water. As flower pots are meant to ‘breathe’ and let in and out water slowly, their are either unglazed or glazed on the edges but not the bottom.  The side glaze, usually in colors and designs, is for aesthetic purposes only.  Flower pots also have a hole in the bottom.

There are Asian terra cotta figurines, glazed but with parts and often the bottom unglazed.  The unglazed areas will show the orange or grown terra cotta color and texture. Earthware is often brownish in color too so it can be difficult to tell the difference between an earthenware figure and a terra cotta.  Terra cotta figures are usually much more refined and smooth out the outside, with earthware more basic and folk-style.  Earthenware is usually a bit heavier too.