In Biology:
Lyse means to burst. Cells, particularily animal cells, autolyse when the tissue/animal dies. They become liquidy, change in colour, and tend to smell terribly. The tissue basically begins to rot. This is caused by a self-destruct mechanism, where the lysosomes release digestive enzymes.

In Baking:
A way of relaxing dough to maximize glutens and enhance extensibility without fermentation.