It often appears in scientific terms, particularly in biology and chemistry, where it refers to the breakdown or disintegration of a substance.
Here are some examples:
* Lysis: The breakdown of a cell by a process that damages its cell membrane.
* Hydrolysis: The breakdown of a compound by the addition of water.
* Electrolysis: The breakdown of a substance by the passage of an electric current.
So, whenever you see "lys" in a word, it usually indicates a process of breaking down or dissolving something.