pelvic girdle is part of the appendicular skeleton
The appendicular skeleton is the portion of the skeleton of vertebrates consisting of the bones that support the appendages. Appendages appeared as fins in early fish, and subsequently evolved into the limbs of tetrapods. The appendicular skeleton includes the skeletal elements within the limbs, as well as supporting pectoral and pelvic girdles in the case of tetrapods (these are lacking in fish). The word appendicular is the adjective of the noun appendage, which itself means a part that is joined to something larger.
Appendicular skeleton