This word is from the Spanish word baƱera (meaning: bath tub).

bathtub, washtub

The word banyera has come to have an extended meaning in Tagalog. Other containers that are not necessarily used for bathing or washing laundry can also be referred to as banyera. For instance, in the title of Filipino television show Prinsesa ng Banyera, the banyera refers to a fish bucket.

Prinsesa ng Banyera
Fishbucket Princess

banyerang paliguan
tub for bathing

isdang banyera ang benta
fish sold by the bucket

banye-banyerang isda
loads of fish

It usually refers to a container that is relatively flat and wide.