recurrent

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Occurring or appearing again or repeatedly.
• adjective Anatomy Turning in a reverse direction. Used of blood vessels and nerves.

from The Century Dictionary.

• In paleontology, reappearing without essential change in organic composition: used of faunas which reappear after their first disappearance from a given geological section, or of a species which thus returns after departure. The conception of recurrent faunas implies the fact of migration and temporary absence from a given geographical province with subsequent return thereto.
• noun A recurrent verse.
• Recurring; returning from time to time; reappearing; repeated: as, recurrent pains of a disease.
• In crystallography, noting a crystal which exhibits an oscillatory combination of two sets of planes. See oscillatory.
• In anatomy, turned back in its course, and running in a direction the opposite of its former one: specifically noting the inferior laryngeal branch of the pneumogastric. See the following phrases.
• In entomology, turning back toward the base: as, a recurrent process.
• A branch which is more or less turned toward the base of the wing, in a direction contrary to the nervure from which it arises. Many of these recurrent nervures are distinguished.
• A vein of the wing which, after running toward the apex, is bent or curved back toward the base, as in many Coleoptera.
• The anterior, a larger branch, arising just behind the perforation of the Interosseous membrane, and anastomosing with the lower articular popliteal arteries.
• The posterior, arising a little lower than the anterior (though they often have a common origin), and communicating with the inferior profunda, the anastomotic, and posterior interosseous recurrent.
• noun Any recurrent nerve or artery.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Returning from time to time; recurring.
• adjective (Anat.) Running back toward its origin.
• adjective (Med.) See Relapsing fever, under Relapsing.
• adjective (Physiol.) the pulse beat which appears (when the radial artery is compressed at the wrist) on the distal side of the point of pressure through the arteries of the palm of the hand.
• adjective (Physiol.) the sensibility manifested by the anterior, or motor, roots of the spinal cord (their stimulation causing pain) owing to the presence of sensory fibers from the corresponding sensory or posterior roots.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Recurring time after time.
• adjective mathematics non-transient.
• adjective Running back toward its origin.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective recurring again and again