Bathtub
noun
The tank you bathe in is a bathtub. Unless you're bathing in like... the town's water supply. If you are, please stop. I don't want to drink your bathwater.
よくそう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
毎日掃除をしないと、浴槽には垢がたまります。
When I don’t clean it everyday, the bathtub accumulates grime.