Short answer: in everyday use, "international driving license" and "international driving permit" refer to the same type of document. The terms are used interchangeably by travelers, and both describe a multi-language translation of your domestic license.
"International Driving Permit" (IDP) is the more formal, treaty-based term, tracing back to international road traffic conventions. "International Driving License" is the everyday phrase most people search for and use in conversation. Functionally, they describe the same kind of document: a translated companion to your existing driver's license.
Whichever term you use, the document works the same way: it sits alongside your original driver's license, restates your details in multiple languages, and is intended to help rental agencies and officials abroad quickly verify who you are.
If you see either term used on a rental company's website or at a checkpoint, you can treat them as referring to the same category of document. Entry, driving, and car-rental requirements can change and vary by destination. Always confirm current rules with the relevant embassy, consulate, or local authority before you travel.