당일 배송이 · 당일 배송을
same-day delivery
Example
오전에 주문하면 당일 배송이 돼요.
If you order in the morning, it's delivered the same day.
Word parts
당 this, that+일 day+배 distribute+송 send
당일 'the very day' + 배송 'delivery' (literally 'distribute and send').
Good to know
Compare 익일 배송 'next-day delivery' and 새벽 배송 'early-morning delivery'.