The Harry Potter franchise is packed full of magical beings and fantastical creatures spilling into the Muggle world, from wizards, goblins, House-elves, and more. But the opposite is also true. While they aren't often mentioned or expanded in the Harry Potter films, there are non-magical beings in the Wizarding World called Squibs. The term "Squib" is only used in the Harry Potter films once and is never really explained, but it is an interesting phenomenon in the series nonetheless.
Source：https://www.cbr.com/harry-potter-squib-explained/
