This is probably a dumb question but what's a referral?

its when somebody comes to da site and u told them about it, so they rite ya name down in referals

like if you ever applied for a job. on the app. it says "who referred you yo us" its like. did anyone tell you that we were hireing? so. for a site it be like who told you about our site. then if someone refered you they might get some credit for you comming on to the site. sum like that.