1.
hot water, heated water
Water that has been heated, as opposed to cold water.
2.
bath water
Hot water prepared for bathing.
Let me know when the bath is ready.
たまる means 'to accumulate'; here it refers to the bathtub filling up
お湯 is the polite/everyday word for hot water. The お prefix is honorific but is almost always used; 湯 alone sounds old-fashioned or literary.
COMMON PATTERNS:
- お湯を沸かす (to boil water)
- お湯を入れる (to pour/add hot water)
- お湯が出る (hot water comes out)
- お湯に入る (to take a bath)
RELATED WORDS:
- 水 (cold water)
- 温い (lukewarm)
- 熱い (hot)
NOTE: In bath contexts, お湯に入る means 'to take a bath' (literally 'to enter the hot water').