Warchalking is the act of adding a simple symbol (presumably in chalk) to the sidewalk or wall near where a wireless 802.11 signal is available. The symbol denotes what sort of Internet access is available and whether or not WEP or other security is used to protect the wireless network. The warchalking idea is based on the hobo sign languages of the early 20th century in the USA. {This word was sent out recently by Paul McFedries.} Example: Calvin has been busy warchalking the wireless nodes, the hotspots, all over the city.
WARCHALKING
Meaning of WARCHALKING in English
Slang English vocab. Английский сленговый словарь. 2012