noun
one-drink minimum; one-drink policy
A system at restaurants, bars, or karaoke where each customer must order at least one drink, often as a condition of entry or seating.
このカラオケ店はワンドリンク制です。
This karaoke place has a one-drink minimum.
ワンドリンク制なので、まず飲み物を注文してください。
Since it's a one-drink policy, please order a drink first.