through mail 意味

• 郵送により、郵送の途中で
  

例文

1. i bought this special knife through mail order with
   通販で買った特製の包丁だよ
2. i told both father and mother through mail
   父上にも母上にも文で伝えてありますので、
3. they sell those through mail order ?
   通販で売ってんの
4. he won't talk to me directly so i thought it might be easier through mail .
   直接は駄目でも 手紙ならって 思ったんですけどね。