from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Informal Something or someone whose name has been forgotten or is not known.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A thing (used in a vague way to refer to something whose name one cannot recall, or that one is embarrassed to say)
From What's it (called)?(American Heritage® Dictionary of the English Language, Fourth Edition)