noun
The initial charge for a taxi, bus, or train ride, before distance or time-based additions. Common in transportation contexts.
タクシーの初乗り料金は500円です。
The taxi's base fare is 500 yen.
このバスの初乗り料金はいくらですか。
How much is the minimum fare for this bus?
Compound of 初乗り (first ride) + 料金 (fee). The exact historical derivation is uncertain, but the term is straightforwardly formed from its components.