Collier's New Encyclopedia (1921)/A
A, a, the first letter in the English alphabet, as in those of all the modern Indo-European tongues. The Latin alphabet also commences with a, and the Greek with a similar letter, alpha. In Sanscrit the vowels are classified by grammarians separately from the consonants. The vowels are placed first, and two sounds of a, the first a very short one, intermediate between ă and ŭ, as in the word Veda, and the other long, as in the first syllable of Brahman, head the list. In the Semitic, also, more accurately called the Syro-Arabian, family of languages, a letter with the a sound stands first in order. Thus the Hebrew alphabet commences with A (Aleph), followed in succession by B (Beth), C (Gimel), D (Daleth), designations which at once suggest the names of the Greek letters Alpha, Beta, Gamma, Delta. The old Hebrew, the Aramæan , and the Greek letters seem to have come from the Phœnician, a Syro-Arabian tongue. The Phœnician letters, again, as Gesenius suggests, may have been derived from the Egyptian hieroglyphics.
A as an initial is used:
- In chronology, for Anno (Lat.)=in the year, as A. D., Anno Domini=in the year of our Lord; A. U. C., Anno urbis conditæ=in the year of the city founded—i. e., from the foundation of the city (Rome)=753 B. C. (Varro).
- In horology, for the Lat. prep. ante=before, as a. m. (ante meridiem)=before noon.
- In designating university degrees, for Artium, as A. M. (Lat.), or M. A. (Eng.), Artium Magister=Master of Arts; A. B. (Lat.), or B. A. (Eng.), Artium Baccalaureus=Bachelor of Arts.
- In music, for alto, as S. A. T. B.=soprano, alto, tenor, bass.
- In nautical language, for able. Thus, A. B.=able-bodied seaman.
- In commerce, for accepted, and is used specially of bills.
A as a symbol stands for:
- In logic, a universal affirmative.
- In music, the 6th note of the diatonic scale of C major corresponding to the la of the Italians and the French.
- In heraldry, the chief in an escutcheon.
- In nautical language, A-1=a vessel of the first class, excellently built. Figuratively, anything highly excellent; the best of its class.
- In mathematics, A and the other letters of the alphabet are used, e. g., in Euclid, to represent lines, angles, points, etc. In algebra, a and the other first letters of the alphabet are used to express known quantities, and the last letter to express such as are unknown.