lunch money; money for a boxed lunch
Money set aside or given for buying a bento (boxed lunch), often used in contexts like school or work allowances.
毎月、弁当代として五千円もらっている。
I receive 5,000 yen every month as lunch money.
Compound of 弁当 (bentō, 'boxed lunch') + 代 (dai, 'charge, fee').