A catch all term for any trade that has a debit on one side (call or put) and a credit on the other. The purpose is to have the credit side pay for the debit side. The play is directional in the direction of the debit side.
Example: long bias in AAPL
long 150/155 call vertical at a debit
short 140/120 put vertical at a credit
Depending on where you are positioning, your size on either side may not be equal. For instance, if you have a debit structure of one vertical on the call side that costs $2, you might consider selling four put verticals at $0.50 to pay for it.
