You can define an application and complete application for your institution. A prequalification is not an application (unless you decision it). Pulling credit on something that is not an application is something that some people do not like though. You can find plenty of posts debating it on BOL.
3. When an inquiry or prequalification request becomes an application. A creditor is encouraged to provide consumers with information about loan terms. However, if in giving information to the consumer the creditor also evaluates information about the consumer, decides to decline the request, and communicates this to the consumer, the creditor has treated the inquiry or prequalification request as an application and must then comply with the notification requirements under ยง 1002.9. Whether the inquiry or prequalification request becomes an application depends on how the creditor responds to the consumer, not on what the consumer says or asks. (See comment 9-5 for further discussion of prequalification requests; see comment 2(f)-5 for a discussion of preapproval requests.)