Dictionary
last' word'
1. the closing remark or comment, as in an argument:
By the rules of debate she would have the last word.
2. a final or definitive work, statement, etc.:
This report is the last word on the treatment of arthritis.
3. the latest, most modern thing:
Casual hairdos are the last word this season. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.