1. antigram an anagram that means the opposite of the original word or phrase
  2. agnostic a person who claims the existence of God is unknowable
  3. anagram a phrase rearranged from the letters of another phrase
  4. histogram a bar chart representing a frequency distribution
  5. pentagram a star with 5 points
  6. instigate provoke or stir up
  7. enneagram a system for classifying personality types
  8. indecorum a lack of decorum
  9. isogram a line drawn on a map connecting points having the same numerical value of some variable
  10. Venn's diagram a diagram that uses circles to represent mathematical or logical sets pictorially inside a rectangle (the universal set); elements that are common to more than one set are represented by intersections of the circles
  11. instar an insect or other arthropod between molts
  12. anestrum applies to nonhuman mammals: a state or interval of sexual inactivity between two periods of estrus
  13. angiogram an X-ray representation of blood vessels made after the injection of a radiopaque substance
  14. ideogram a graphic character that indicates the meaning of a thing without indicating the sounds used to say it
  15. mainstream the prevailing current of thought
  16. unstarred not marked with an asterisk
  17. instigant someone who deliberately foments trouble
  18. onstage on the stage
  19. in stages a little bit at a time
  20. instigator someone who deliberately foments trouble