Definition of 投書箱 (とうしょばこ)
とうしょばこ
                        投書箱
とうしょばこ
toushobako
noun
•
        
suggestion box, complaints box
Related Kanji
| 投 | throw, discard, abandon, launch into, join, invest in, hurl, give up, sell at a loss | 
| 書 | write | 
| 箱 | box, chest, case, bin, railway car |