noun
discounted hours; reduced rate hours
Refers to time periods when a discount or reduced rate applies, such as off-peak hours for electricity, phone calls, or services.
このプランは割引時間に電話をかけるとお得です。
With this plan, it's cheaper to make calls during discounted hours.
電気料金の割引時間は夜間です。
The discounted hours for electricity rates are at night.
割引 means 'discount' in general, while 割引時間 specifically refers to the time period when the discount is applied.
Compound of 割引 (わりびき, 'discount') and 時間 (じかん, 'time, hours').