A dot above a letter is known as a 'diacritic dot'. The common name for the diacritic dot above an i or a j is a 'tittle'.

See wikipedia for "caron". A "Czech mark" can refer to a diacritic placed over a letter in order to change the sound value. See also wikipedia for "diacritic"

See wikipedia for "caron". A "Czech mark" can refer to a diacritic placed over a letter in order to change the sound value. See also wikipedia for "diacritic"

An anusvara is a diacritic used in the Devanagari script to indicate a nasal consonant.

You could use the diacritic called the macron: ā. So the name would be Zāv. People would have to be informed that the z sounds like s.