1. A the 1st letter of the Roman alphabet
  2. Abecedarian a 16th century sect of Anabaptists centered in Germany who had an absolute disdain for human knowledge
  3. 1000000000 the number that is represented as a one followed by 9 zeros
  4. Aaron's rod tall-stalked very woolly mullein with densely packed yellow flowers; ancient Greeks and Romans dipped the stalks in tallow for funeral torches
  5. 1000000000000 the number that is represented as a one followed by 12 zeros
  6. Abney level a surveying instrument consisting of a spirit level and a sighting tube; used to measure the angle of inclination of a line from the observer to the target
  7. .22 caliber of or relating to the bore of a gun (or its ammunition) that measures twenty-two hundredths of an inch in diameter
  8. Aborigine a dark-skinned member of a race of people living in Australia when Europeans arrived
  9. .38 calibre of or relating to the bore of a gun (or its ammunition) that measures thirty-eight hundredths of an inch in diameter
  10. .38 caliber of or relating to the bore of a gun (or its ammunition) that measures thirty-eight hundredths of an inch in diameter
  11. Abel Tasman Dutch navigator who was the first European to discover Tasmania and New Zealand (1603-1659)
  12. .45 caliber of or relating to the bore of a gun (or its ammunition) that measures forty-five hundredths of an inch in diameter
  13. .22 calibre of or relating to the bore of a gun (or its ammunition) that measures twenty-two hundredths of an inch in diameter
  14. Aaron Burr United States politician who served as vice president under Jefferson; he mortally wounded his political rival Alexander Hamilton in a duel and fled south (1756-1836)
  15. 1-dodecanol a colorless insoluble solid alcohol used to make detergents and pharmaceuticals
  16. .45 calibre of or relating to the bore of a gun (or its ammunition) that measures forty-five hundredths of an inch in diameter
  17. 401-k plan a retirement savings plan that is funded by employee contributions and (often) matching contributions from the employer; contributions are made from your salary before taxes and the funds grow tax-free until they are withdrawn, at which point they can be converted into an IRA; funds can be transferred if you change employers and you can (to some extent) manage the investments yourself
  18. A. A. Milne English writer of stories for children (1882-1956)
  19. Abelmoschus genus of tropical coarse herbs having large lobed leaves and often yellow flowers
  20. AND circuit a circuit in a computer that fires only when all of its inputs fire