A strangle is an option strategy where both long and short position is taken (buy call + buy put) on the same instrument with the same expiry but at different strikes. The call has a
strike price above the current price of the underlying instrument and the put has a strike below the current price of the underlying.
This strategy is used to anticipate a big move in the price of the underlying in either direction (up or down).
The price movement needs to be bigger than in the case of a
straddle but the premiums to be paid are smaller because the options are "out-of-the-money".