Big Dipper, Measure Of Volume, Eighteen Liters
Noun
と
一斗のお米が入った袋は置いてますか？
Do you have a bag of 18 liters of rice?
How much can you hold in this ladle? Why, exactly eighteen liters of course! Eighteen is your favorite number, how convenient.
The reading is the same as the one you learned with the kanji.