The SLT label is on Dodge trucks, and it shows what level of trim that model has. For example, there are five different trim levels for the Dodge RAM Pickup 1500 truck. The ST, SLT, TRX, Sport, and Laramie packages are listed in that order.
The SLT title is not an official acronym, so it does not spell out a series of words. The SLT is a slight improvement over the stock truck. It usually comes with a longer truck bed and a 5-speed automatic transmission instead of the 4-speed automatic transmission that comes with the stock truck. Compared to the SLT model, the high-end Dodge Laramie is usually a limited edition or a luxury cab.