老朋友用英语怎么说

"老朋友"在英语中可以翻译为"old friend"。这个短语来源于拉丁语，"老"在拉丁语中是"vetus"，意思是"old"，"朋友"在拉丁语中是"amicus"，意思是"friend"。因此，将这两个词结合在一起就可以得到"老朋友"的意思。

下面是一些例句：

He is my old friend. (他是我的老朋友。)
She has known him since they were kids. He is her old friend. (她从小就认识他了。他是她的老朋友。)
I'm glad to see you again. It's been a long time since we last saw each other. You're still my old friend. (很高兴再次见到你。我们上次见面已经很久了。你仍然是我的老朋友。)