English version comes after Japanese.
日本語で「ベテラン」というと熟練者のことですね。英語で「veteran」と書きますが、退役軍人を意味することが多いです。もちろん話の内容によりますが「退役軍人」の意味を知らずに「彼は勤続20年のveteranだ」のように使うと話がかみ合わなくなるかもしれないので要注意。
"Veteran" is one of the English words used in a very narrow meaning "a skilled worker" in Japan. I understand the word "veteran" is generally used in the context of military service. If I look up in the dictionary the word has both meanings. Because the military related usage isn't widely known in Japan, if you hear a Japanese person use "veteran", s/he most likely means a skilled worker.