Hard inquiry
A credit check made when you apply for credit, like a card, loan or mortgage. It can lower your score a few points for a while.
A lender makes a hard inquiry when you apply for new credit, and only with your permission. It shows on your credit report for about 2 years, but its effect on your score usually fades sooner.
Several applications in a short time can add up. Scoring models usually count multiple checks for the same kind of mortgage, auto or student loan within a short window as one, so you can shop for the best rate.