In one line
A combination is two or more option contracts held together, and the reason for holding them together is that the pair has a payoff shape that neither leg has on its own.
How it works
A STRADDLE is a call and a put at the same strike and expiry. Held, it pays when the index travels far in either direction and loses when it sits still; written, the reverse. It is the least design-dependent structure there is, which is why this desk used it to measure whether volatility was richly priced rather than as a position.
A STRANGLE is the same idea with the two legs at different strikes, both out of the money. It costs less than a straddle and needs a larger move to be worth anything.
A VERTICAL SPREAD is two contracts of the same kind at different strikes, one held and one written. The written leg pays for part of the held one and caps what the pair can be worth. Both the most it can be worth and the most it can cost are known at the start, which is the whole reason the shape exists.
An IRON CONDOR is two vertical spreads, one on each side, and a BUTTERFLY is three strikes with the middle one doubled. Both are bounded on every side.
The desk's builder draws the payoff of any of these at expiry exactly, since the shape is straight lines between the strikes. Before expiry it is a MODEL, computed separately and named separately, so that nobody gets one thinking they have the other.
What it is not
No shape here is better than another and none of them is a position this desk proposes. A capped payoff is not a safe one — the cap is on the size, not on the frequency — and an unbounded one is reported as unbounded rather than as the number at the edge of whatever range happened to be drawn.