On a 2000 Chevy Silverado Z71 what does the LS and LT stand for?

On a 2000 Chevy Silverado, LS and LT don't stand for anything related to the Z71 off-road package. Instead, LS and LT represent different trim levels. They signify different levels of standard features and equipment. The Z71 is an *additional* package added to either the LS or LT trim (or other trims).

* LS: Generally the base or near-base trim level. It would have fewer standard features than the LT.

* LT: A higher trim level than the LS, offering more standard features, comfort, and sometimes convenience options.

So a "2000 Chevy Silverado Z71 LS" would be a Z71 off-road package added to a base-level LS trim, while a "2000 Chevy Silverado Z71 LT" would have the Z71 package on a higher-equipped LT trim.