U+12000 Cuneiform Sign A

The Wikipedia has the following information about this codepoint:

The cuneiform sign 𒀀 (DIŠ, DIŠ OVER DIŠ) for a, and in the Epic of Gilgamesh the sumerogram A, Akkadian for mû, "water", which is used in the Gilgamesh flood myth, Chapter XI of the Epic, or other passages. The sign is also used extensively in the Amarna letters.

Cuneiform a is the most common of the four vowels in the Akkadian language, a, e, i, and u. All vowels can be interchangeable, depending on the scribe, though spellings of Akkadian words in dictionaries, will be formalized, and typically: unstressed, a 'long-vowel', or thirdly, a 'combined' vowel (often spelled with two signs (same vowel, ending the first sign, and starting the next sign), thus combined into the single vowel, â, ê, î, or û.). Cuneiform a is the most common of the four vowels, as can be shown by usage in the Epic of Gilgamesh, the usage numbers being (ú (u, no. 2) is more common than u, (no. 1), which has additional usages, numeral "10", and "and", "but", etc.): a-(1369), e-(327), i-(698), ú-(493). (For u, only: u-(166)); The usage for a, includes the usage for Akkadian a-na, (ana), the preposition, "for", "to", etc., about 250 usages (therefore usage: 1369–250).