Here's a breakdown:
* Sabon means "soap"
* Sa means "for" or "in"
* Buhok means "hair"
Therefore, sabon sa buhok literally translates to "soap for hair."
You may also see other translations like:
* Shampoo - This is simply the English word adopted into Tagalog.
* Pantulak ng dumi sa buhok - This literally means "dirt remover for hair."
Ultimately, the best translation will depend on the specific context.