What is the meaning of as?

noun

• A metric unit of length equal to one ten billionth of a meter (or 0. 0001 micron); used to specify wavelengths of electromagnetic radiation.
  • synonyms: angstrom, angstrom unit, A
• Any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes.
  • synonyms: vitamin A, antiophthalmic factor, axerophthol, A
• One of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose.
  • synonyms: deoxyadenosine monophosphate, A
• Biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA.
  • synonyms: adenine, A
• The basic unit of electric current adopted under the Systeme International d'Unites.
  • usage: "a typical household circuit carries 15 to 50 amps"
  • synonyms: ampere, amp, A
• The 1st letter of the Roman alphabet.
  • synonyms: A, a
• The blood group whose red cells carry the A antigen.
  • synonyms: A, type A, group A
• A very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar.
  • synonyms: arsenic, atomic number 33
• A United States territory on the eastern part of the island of Samoa.
  • synonyms: American Samoa, Eastern Samoa

adverb

• To the same degree (often followed by `as'. )
  • usage: "they were equally beautiful"; "birds were singing and the child sang as sweetly"; "sang as sweetly as a nightingale"; "he is every bit as mean as she is"
  • synonyms: equally, every bit