LSD stands for limited slip differential. Basically a limited slip differential will split the power evenly between the rear wheels and will continuously give more power to the wheel that grips versus the one that is slipping. The alternative is an "open differential" which will basically give the power to the wheel that's slipping the most..
New cars have "electric" open diffs that are kind of like LSD's but they just use the brakes to control wheel slippage, rather than doing it inside the diff which is much preferred.
For 90% of the population they won't know the difference.
1994 Infiniti Q45- First 5-speed swapped Q45.
2007 BMW M Coupe