Definition of a - WordReference.com Dictionary

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Adapted From: WordNet 2.0 Copyright 2003 by Princeton University. All rights reserved.

a
A	noun
	1	A
			the 1st letter of the Roman alphabet
		Category Tree: abstraction ╚relation ╚social relation ╚communication ╚signal; signaling; sign ╚symbol ╚written symbol; printed symbol ╚character; grapheme; graphic symbol ╚letter; letter of the alphabet; alphabetic character ╚A
	2	A, type A, group A
			the blood group whose red cells carry the A antigen
		Category Tree: group; grouping ╚people ╚blood group; blood type ╚A, type A, group A
	3	ampere, amp, A
			the basic unit of electric current adopted under the Systeme International d'Unites; "a typical household circuit carries 15 to 50 amps"
		Category Tree: abstraction ╚measure; quantity; amount ╚definite quantity ╚unit of measurement; unit ╚electromagnetic unit; emu ╚current unit ╚ampere, amp, A
	4	angstrom, angstrom unit, A
			a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
		Category Tree: abstraction ╚measure; quantity; amount ╚linear measure; long measure ╚linear unit ╚metric linear unit ╚angstrom, angstrom unit, A
	5	adenine, A
			(biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
		Category Tree: entity ╚substance; matter ╚compound; chemical compound ╚base; alkali ╚purine ╚adenine, A
	6	deoxyadenosine monophosphate, A
			one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
		Category Tree: entity ╚substance; matter ╚compound; chemical compound ╚organic compound ╚ester ╚nucleotide ╚deoxyadenosine monophosphate, A
	7	vitamin A, antiophthalmic factor, axerophthol, A
			any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
		Category Tree: entity ╚substance; matter ╚food; nutrient ╚nutriment; nourishment; nutrition; sustenance; aliment; alimentation; victuals ╚vitamin ╚fat-soluble vitamin ╚vitamin A, antiophthalmic factor, axerophthol, A ╚vitamin A2; dehydroretinol ╚vitamin A1; retinol

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