short vowel marks / diacritics / حركات (ḥarakāt)

The short vowels ḍamma, fatḥa, kasra, shidda and sukūn that are placed above or undearneath letters but not written in most texts except for reasons of clarifications or in the Quran.

The small vowels are also called: حروف مصغرة  ḥurūf muṣaġġara (“reduced letters”).