Definitions by Morei

Siphon 

In various video games, used as a keyword for take out life points out of something (usually your opponent or an object) to transfer it to your own character. Mostly used for HP transferring.

Sometimes referred as Lifesteal in specific games.

My opponent siphoned all my health in 2 seconds.

Hearthstone:

Siphon Soul - 6 Mana: Destroy a minion and restore 3 Health to your Hero.

Siphon by Morei April 11, 2019