Point O is between points Mand N on line segment MN. O is the midpoint of line segment MN if ON = NM
OM = NM
ON + OM = MN
ON = OM

Diagram:
MON
^ midpoint
Obviously if O is the *mid*point, then it is exactly halfway between M and N. That also means it has bisected the segment into two equal parts.
On one side you have MO (or OM, if you like)
On the other side you have ON.
In order for O to be the midpoint:
ON = OM

In most cases we treated them negatively (If you of course exclude the pilgrims but that's a totally different issue) but is this tied to a lesson, may you specify so i can give the best answer of my knowledge? I was/am currently learning about Jamestown, Virginia and in that case it was the opposite, they started the mistreatment towards the USA first.

Have a great day, hun!