Aside (adv.) On, or to, one side; out of a straight line, course, or direction; at a little distance from the rest; out of the way; apart.

Aside (adv.) Out of one's thoughts; off; away; as, to put aside gloomy thoughts.

Aside (adv.) So as to be heard by others; privately.

Aside (n.) Something spoken aside; as, a remark made by a stageplayer which the other players are not supposed to hear.