Siddham Letter O

It writes an unaccompanied Sanskrit o vowel.

Siddham grew from Brahmi, an older North Indian writing system; its Gupta-period form took shape during the Gupta dynasty’s rule in northern India. Vowels were taught as a set: students recited each alone, then paired each with every consonant. Inscriptions of forms called Siddhamatrika or Kutila are attested from the sixth to about the tenth century.

Buddhist manuscripts and teachers carried Siddham from India into Central and East Asia. Related North Indian script lines developed toward Sharada, Gauḍī/Proto-Bengali, and Nāgarī. In Japan, Buddhist communities preserved it for Sanskrit mantras and dhāraṇīs—ritual chants and formulas—giving its letters a devotional role.

Is Siddham O the independent vowel or the o sign?

𑖌 is standalone; 𑖺 attaches to a consonant.

Use 𑖌 when a syllable begins with o. Use 𑖺 after a consonant to change that consonant’s built-in vowel to o.