What does "CW" stand for on Channel 5, Kansas City, Mo?

Answer 1

The CW Network is a joint venture between the old WB Network of Warner Brothers and the Columbia Broadcasting System (CBS). Hence, the "C" for CBS and the "W" for WB.
It replaced both the WB Network and the UPN Network started by Paramount Pictures.

Answer 2

The CW Network is a joint venture of CBS Corp and Time Warner - a merger between the old UPN and WB networks.

Also, Channel 5 is the CBS channel in KC; 29 is the CW channel.