What is the meaning of the words "al-khiṭān" (circumcision) and "al-istiḥdād" (use of depilatory) in the noble Prophetic tradition (Hadith)?

The Prophet, peace and blessings be upon him, said: "Five are from the fitra (primordial nature): circumcision, removing pubic hair, plucking armpit hair, clipping nails, and trimming the mustache." Circumcision is the cutting of the foreskin that covers the glans of the man, and the cutting of some of the skin on the upper part of the woman's vulva. As for istihdad (removing pubic hair), it is the removal of pubic hair with iron, which is the hair that grows above and around the male penis and the female vulva.