Are yams and sweet potatoes the same?
indefinite article, mid-12c., a variation of Old English an (see an) in which the -n- began to disappear before consonants, a process mostly complete by mid-14c. The -n- also was retained before words beginning with a sounded -h- until c.1600; it still is retained by many writers before unaccented syllables in h- or (e)u-, but is now no longer normally spoken as such. The -n- also lingered (especially in southern England dialect) before -w- and -y- through 15c.
as in twice a day, etc., from Old English an "on," in this case "on each." The sense was extended from time to measure, price, place, etc. The habit of tacking a onto a gerund (as in a-hunting we will go) died out 18c.
specific absorption coefficient (often italic)
systemic arterial blood (used as a subscript)
absorbance (often italic)
alveolar gas (used as a subscript)
AMP (in polynucleotides)
Abbreviation of adenine, ampere, angstrom, area
Abbreviation of angstrom
Alpha, the first letter of the Greek alphabet, as Omega is the last. These letters occur in the text of Rev. 1:8,11; 21:6; 22:13, and are represented by "Alpha" and "Omega" respectively (omitted in R.V., 1:11). They mean "the first and last." (Comp. Heb. 12:2; Isa. 41:4; 44:6; Rev. 1:11,17; 2:8.) In the symbols of the early Christian Church these two letters are frequently combined with the cross or with Christ's monogram to denote his divinity.