Alkoxymercuration-Demercuration Definition:

A two-step process that achieves Markovnikov addition of an alcohol (H and OR) across an alkene. The product of this process is an ether.

Alkoxymercuration-Demercuration process

From the reaction scheme above, you can see that the alkene was broken and an ether (OR) was added to the more substituted side, while the hydrogen (H) was added to the less substituted side.