[countable] one of a set of small boxes that are fixed on a wall and open at the front, used for putting letters, messages, etc. in信件架；文件格◆The letter had been put in the wrong pigeonhole.那封信放错信件架了。a group or type of people or things that sb/sth is put into, that is often too general, unfair or not correct（被置于过于宽泛、不公平的或错误的）群体；类型◆Many clients want their advisers to fit into neat pigeonholes.许多客户想把他们的顾问简单地分类。 SYN category