(cricket) The side of the pitch on the same side as the batsman's legs as he takes his stance at the wicket; the left side for a right-handed batsman.

(cricket) The side of the pitch away from the batsman's legs as he takes his stance at the wicket; the right side for a right-handed batsman. / (horsemanship) The right-hand side of a horse.

(economics) Regarding the supply side of the economy.

(economics) In a market trade, the side where the supply comes from.

(slang, baseball, dated, 19th c.) three outs.

The female or maternal branch of a family.

Alternative spelling of side effect

To alter as a side effect.

An unintended consequence of any action in addition to the intended consequence of that action.

(sports) A play in American football whereby the team performing the kick-off kicks the ball the minimum distance (ten yards in most levels of play) in an attempt to immediately regain possession of the ball.