1. The cardinal number equal to the sum of 15 + 1.
2. The 16th in a set or sequence.

[Middle English sixtene, from Old English sixtȳne.]

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.