What is the synonym of commence?

Here are some synonyms for "commence," depending on the context:

General synonyms:

* Begin

* Start

* Initiate

* Launch

* Open

* Undertake

* Embark on

* Set about

* Get going

* Set in motion

More formal synonyms:

* Inaugurate

* Inaugurate

* Enter upon

* Institute

* Introduce

More informal synonyms:

* Kick off

* Get started

* Get underway

The best synonym to use will depend on the specific context of your writing.