[nerd] Can I use my app from iPod on new iPhone?

I currently have an iPod 4G and my iPhone 5 is in process and it will be shipped next week.

Now, I want to buy the Longman Dictionary app for academic purpose on my iPod at this time. I don't have enough money to buy the same app for 2 different devices, so can I use it on my new iPhone?

I use for individual purpose only, not for any one Apple devices else and I have never bought any apps or even jail-broken.

Th@nk for advices!