undated letter无日期的信
undated stock未注明日期的证券;无偿付期政府金边债券
undated bonds不定期公债
undated cheque未注日期支票
undated reference标准文献分类;不注明日期的引用
Undated d无日期的;不限日期既
undated deposit[金融] 不定期存款
undated securities不定期证券
undated bill无日期票据
ADJ（形容词） Something that is undated does not have a date written on it. 未标注日期的
In each packet there are batches of letters, most of which are undated.
每个包里都有成捆的信件，大部分都是未标注日期的。