the world > space > relative position > quality of having sides or being a side > [adverb] > on one or both sides (3)
To or on one side. Cf. sideling, adv. 2a. Obsolete (Scottish and English regional (northern) in later use).
In a unilateral manner. Botany, Zoology, and Pathology. On one side or surface only.
in a bilateral manner, on both sides.