from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A lengthy television program to raise funds for a charity.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An event that brings in people to donate money through the phone via the television (TV).
tele- + (mara)thon.(American Heritage® Dictionary of the English Language, Fourth Edition)
A blend of telephone and marathon (Wiktionary)