Dictionary.com's Word of the Year is...
1911, "high pitched sound," 1918, of echoic origin. Slang meaning "energy, zest" is attested from 1918.
Energetic vitality; power; vigor; oomph, pep, pizzazz, zip: Rock adds zing/ with plenty of zing in both the V-8 engine and the powerful Six (1918+)
[probably echoic of the whishing sound of rapid movement, like zip and zoom]