Absolutely - this is an amazing way to provide partners and VIPs with discount codes, but not have the code be re-used by just anybody.
When creating a discount code, set the Number Available to determine how many times this code can be used.
This is the number of orders the discount code can be applied to. If a buyer purchases 10 tickets in a single order, this will only count as one use of the discount code.
If you're looking to limit one discount code per person, check out the "Limit One Order per Email" option in the Tickets tab.
*Disclaimer: Currently, when a discount code is used, it applies to an entire order even if it is designed to be used only once. This means that if a guest purchases two tickets in a single order with a discount code meant to only be used once, the code will still apply to both tickets.
However, we are working on improving this experience so that limitations on discount codes can be more manageable.