Yes, there is. You probably know the word for and -> وَ.
But there are other forms too. They are rare and only possible in the imperative (أَمْر) of some verbs. These verbs have two weak letters (حَرْف الْعِلّة) in the root and only one “strong” consonant.
One-letter-words in Arabic: Let’s have a look at some examples.
It can be difficult to understand these forms correctly. Let’s have a look at this example:
… وَقِنَا عَذَابَ النَّارِ
|…and protect us from the punishment of the Fire (Sura 2:201)|