1 the system for collecting and sending letters and packages 邮政，邮递（制度）: to send a parcel by airmail/surface mail 以空邮╱平邮邮寄包裹

2 the letters, etc that you receive 邮件；信件: junk mail (= letters, usually advertising sth, that are sent to people although they have not asked for them) 垃圾邮件（自动寄来的邮件，通常是广告宣传品） ☞Look at the note at post. 参看post的注释。

3 (especially US 尤为美) =EMAILmail verb [T] (especially US 尤为美)