The letter A is the first letter in the Roman alphabet.
On computers using ASCII, the uppercase letter is represented with ASCII code 65 and the lowercase letter with code 97.
A is also:
The form of the letter has varied considerably. In the earliest of the Phoenician, Aramaic and Greek inscriptions (the oldest Phoenician dating about 1000 B.C., the oldest Aramaic from the 8th, and the oldest Greek from the 8th or 7th century B.C.) A rests upon its side thus -- @. In the Greek alphabet of later times it generally resembles the modern capital letter, but many local varieties can be distinguished by the shortening of one leg, or by the angle at which the cross line is set-- @, &c. From the Greeks of the west the alphabet was borrowed by the Romans and from them has passed to the other nations of western Europe. In the earliest Latin inscriptions, such as the inscription found in the excavation of the Roman Forum in 1899, or that on a golden fibula found at Praeneste in 1886 (see Alphabet). Fine letters are still identical in form with those of the western Greeks. Latin develops early various forms, which are comparatively rare in Greek, as @, or unknown, as @. Except possibly Faliscan, the other dialects of Italy did not borrow their alphabet directly from the western Greeks as the Romans did, but received it at second hand through the Etruscans. In Oscan, where the writing of early inscriptions is no less careful than in Latin, the A takes the form @, to which the nearest parallels are found in north Greece (Boeotia, Locris, and Thessaly, and there only sporadically) .
In Greek the symbol was used for both the long and the short sound, as in English father (a) and German Ratte a; English, except in dialects, has no sound corresponding precisely to the Greek short a, which, so far as can be ascertained, was a mid-back-wide sound, according to the terminology of H. Sweet (Primer of Phonetics, p. 107). Throughout the history of Greek the short sound remained practically unchanged. On the other hand, the long sound of a in the Attic and Ionic dialects passed into an open e-sound, which in the Ionic alphabet was represented by the same symbol as the original e-sound. The vowel sounds vary from language to language, and the a symbol has, in consequence, to represent in many cases sounds which are not identical with the Greek a whether long or short, and also to represent several different vowel sounds in the same language. Thus the Oxford English Dictionary distinguishes about twelve separate vowel sounds, which are represented by a in English.
In general it may be said that the chief changes which affect the a-sound in different languages arise from (1) rounding, (2) fronting, i.e. changing from a sound produced far back in the mouth to a sound produced farther forward. The rounding is often produced by combination with rounded consonants (as in English was, wall, &c.), the rounding of the preceding consonant being continued into the formation of the vowel sound. Rounding has also been produced by a following l-sound, as in the English fall, small, bald, &c. (see Sweet's History of English Sounds, 2nd ed., sec. sec. 906, 784). The effect of fronting is seen in the Ionic and Attic dialects of Greek, where the original name of the Medes, Madoi, with a in the first syllable (which survives in Cypriot Greek as Madoi), is changed into Medoi (Medoi), with an open e-sound instead of the earlier a. In the later history of Greek this sound is steadily narrowed till it becomes identical with i (as in English seed). The first part of the process has been almost repeated by literary English, a (ah) passing into e (eh), though in present-day pronunciation the sound has developed further into a diphthongal ei except before r, as in hare (Sweet, op. cit. sec. 783).