why is a $10 bill called a “sawbuck”?
From m-w.com
Main Entry: saw·buck
Pronunciation: 'so-"b&k
Function: noun
Date: 1850
1 slang : a 10-dollar bill
2 : SAWHORSE; especially : one with X-shaped ends
Sounds kinda strange, though. Apparently since an “X” is the Roman numberal “10,” and a sawhorse is decussate in nature, someone started calling the 10-dollar bill a sawbuck.
The most common story has it that the Roman numeral for ten, X, looks like a sawbuck seen “in profile.”