两者没有任何区别，其意思是笔友，美式英语中，常用pen pal，英式英语中，常用penfriend。例如make a pen pal交个笔友、a pen pal from Beijing来自北京的一个笔友、a penfriend in American在美国的笔友等等。笔友是一种借着书信往来而发展出来的友谊关系，通常为未见过面而与之友好地继续通信的人。

例句：1、The penfriend society has been set up for the purpose of promoting friendship.

建立笔友会是为了促进友谊。

2、I have not received any message from my penfriend for almost half an year.

我已经大约半年没接到我笔友的消息了。

3、I would very much like to have a pen pal from Beijing.

我非常需要一位来自北京的笔友。

4、Has she been writing to her pen pal all the time？

她一直在给他的笔友写信吗？

5、My Russian pen pal and I have been corresponding for several years.

我的俄国的笔友和我已经通信几年了。