What anatomical term refers to the tailbone?

The term that refers to the tailbone is "Coccyx." This small, triangular bony structure is located at the base of the vertebral column and is composed of three to five fused vertebrae. The coccyx serves as an attachment site for various ligaments and muscles, playing a role in supporting the weight of the body when sitting.

In contrast, the pelvis refers to the bony structure that forms the base of the spine and connects the trunk and legs but does not specifically denote the tailbone. The sacrum is a large, triangular bone located above the coccyx, formed by the fusion of five vertebrae, and it connects to the hip bones. The term vertebrae is a general term for the individual bones that make up the spinal column, which includes the cervical, thoracic, lumbar, sacral, and coccygeal vertebrae. Each of these choices represents important anatomical structures, but only the coccyx specifically identifies the tailbone itself.