The CL stands for the underlying futures contract.
The Z stands for a December delivery month. (F=Jan, G=Feb, H=Mar, J=Apr, K=May, M=June, N=July, Q=Aug, U=Sep, V=Oct, X=Nov, Z=Dec)
The 7 stands for the year 2007.
This is the standard formula for futures ticker symbols. Some quote services are a little different.
- You can visit the Profiles of Commodities to find more specific information on the contracts of each commodity.

