It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version can be written in two forms: the double-storey ⟨a⟩ and single-storey ⟨ɑ⟩.

The phonetic sound of a can vary depending on the word and context. In general, it can have a short sound (like “ă” in “cat”) or a long sound (like “ā” in “cake”). It can also have other sounds, such as the schwa sound (like “ə” in “sofa”) or the “uh” sound (like “ʌ” in “up”).

A with tilde (majuscule: Ã, minuscule: ã) is a letter of the Latin alphabet formed by addition of the tilde diacritic over the letter A. It is used in Portuguese, Guaraní, Kashubian, Taa, Aromanian, and Vietnamese.

The name of the letter in the Phoenician period resembled the Hebrew name aleph meaning “ox”; the form is thought to derive from an earlier symbol resembling the head of an ox. The letter was taken over by the Greeks in the form of alpha.