Velcro is a brand name for a type of fastener that consists of two strips of material: one with tiny hooks and the other with small loops. When the two strips are pressed together, the hooks catch in the loops, creating a secure closure. To open it, you simply pull the strips apart.
Most English native speakers are familiar with “Velcro” as it’s a well-known brand name that has become synonymous with hook-and-loop fasteners. However, the term is often used generically to describe similar fasteners, regardless of the brand. That said, there might be some people who don’t know the brand name but will understand the concept if you describe it as a fastener with hooks and loops that stick together.