1. Lasting for eternity.
2. Continuing or lasting for an indefinitely long time.
3. Instituted to be in effect or have tenure for an unlimited duration: a treaty of perpetual friendship.
4. Continuing without interruption. See synonyms at continual.
5. Flowering throughout the growing season.

[Middle English perpetuel, from Old French, from Latin perpetuālis, from perpetuus, continuous : per-, per- + petere, to go toward.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.