The small bone at the end of the spinal column in man, formed by the fusion of four rudimentary vertebrae The three, and sometimes four, segments of bone just below the sacrum; referred to as the tailbone
The plural coccyges is used in American English. The coccyx is the small triangular bone at the lower end of the spine in human beings and some apes. coccyxes coccyges the small bone at the bottom of your spine = tailbone