a side game or other special activity distinct from a game's regular mode. Can include things like wild symbols, scatter symbols, and free spins. "More and more, slot designers are producing [..]

An extra way to win on top of the regular spins. The most common bonus feature is free spins.

and extra way to win other than the conventional one

A bonus feature is one of the new things that became available after the introduction of video slot machines. A common bonus feature is unlocked by hitting a certain combination of symbols and opens i [..]

An extra game triggered from the reels, which usually offers very large payouts

Bonus features are offered on many slot machines in casinos today. Bonus features include wild cards or symbols and free spins. Bonus Multiplier Slot Machines

Any additional way to win in addition to the reel pays

Slots may include various features to enhance gameplay, such as wild symbols, scatter symbols, free spins or bonus games.

A feature within a slot game that gives you extra ways of winning.