Studying the shortest sūras of the Quran, scholars have noted the relative frequency of Arabic words that appear nowhere else – known as hapax legomena. Sūra 108, the shortest sūra of all, includes two hapax words in important positions.

108.1 – Surely We have given you the abundance
The word translated here as “abundance,” kawthar, gives the sūra its name. However, the meaning of the word is uncertain because it appears only here in the Quran. As such, it has challenged centuries of Muslim commentators and scholars.
A second hapax legomenon in this sūra is the word abtar, translated “one cut off” (v. 3). If these short sūras were first recited early in the preaching of the messenger, as Muslim tradition holds, it seems strange that two important words were never repeated in the many long sūras recited later.