What is the meaning of Damma?

In the Arabic script, the vowel point for u, appearing as a small curl placed above a letter ( ـُ ) and designating a short u /u/. If the Arabic letter و (wāw) immediately follows, it indicates a long ū /uː/.

In Iranian Persian ـُ represents the vowel /o/. If the letter ـو immediately follows it represents the diphthong /ow/. This usage differs from other Arabic script languages and from classical Persian, in which the diphthong /ow/ did not occur.

contraction of dean +‎ ma, literally “do we”

damma

(male or female) fallow deer

A fallow deer

die (polyhedron used in games of chance)

to dam

honey

gerundive of dameti (“to tame”)

in need of taming, in need of restraint

to dust, to remove dust

to raise dust, to be dusty

to eat

Source: Wiktionary