1. extension ladder a ladder whose length can be extended
  2. extension cord an electric cord used to extend the length of a power cord
  3. extensional defining a word by listing the class of entities to which the word correctly applies
  4. extension act of expanding in scope
  5. extension agent an advisor employed by the government to assist people in rural areas with methods of farming and home economics
  6. extension phone an additional telephone set that is connected to the same telephone line
  7. accommodation ladder (nautical) a portable ladder hung over the side of a vessel to give access to small boats alongside
  8. extension course a course offered as part of an extension service
  9. extensible capable of being protruded or stretched or opened out
  10. extensile capable of being protruded or stretched or opened out
  11. extensively in a widespread way
  12. extortionate greatly exceeding bounds of reason or moderation
  13. exterminator someone who exterminates
  14. extensive large in spatial extent or range or scope or quantity
  15. extended order a military formation for skirmishing
  16. extortioner a criminal who extorts money from someone by threatening to expose embarrassing information about them
  17. extensor a skeletal muscle whose contraction extends or stretches a body part
  18. extrapolate draw from specific cases for more general cases
  19. intentionality expressive of intentions
  20. ostensible appearing as such but not necessarily so