Enter upon and Take on

Enter upon verb - Take possession of.

Take on and enter upon are semantically related in activity topic. In some cases you can use "Take on" instead a verb "Enter upon", when it comes to topics like assume, undertake.

Take on verb - To enter into contest or conflict with.

Enter upon and take on are semantically related in activity topic. You can use "Enter upon" instead a verb "Take on", if it concerns topics such as undertake.