pneu·mat·ic (n-mătĭk, ny-) also pneu·mat·i·cal (-ĭ-kəl)
1. Of or relating to air or other gases.
2. Of or relating to pneumatics.
a. Run by or using compressed air: a pneumatic drill.
b. Filled with air, especially compressed air: a pneumatic tire.
4. Zoology Having cavities filled with air, as the bones of certain birds.
5. Of or relating to the pneuma; spiritual.
[French pneumatique, from Latin pneumaticus, from Greek pneumatikos, from pneuma, pneumat-, wind; see pneu- in the Appendix of Indo-European roots.]
pneu′ma·tici·ty (n′mə-tĭsĭ-tē, ny′-) n.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.