What word means toward the side away from midline?

The word that means "toward the side away from midline" is lateral.

Here are some other words that could be used in a similar context:

* Peripheral: This means "relating to or situated on the outer edge of something" and can also be used to indicate a location away from the midline.

* Distal: This refers to a position farther from the center of the body or a point of attachment.

* Abaxial: This specifically refers to the side of a plant or leaf that faces away from the axis or stem.

The specific word you would use would depend on the context and what you are trying to describe.