A prong snap button (also known as a ring snap or popper) is a 4-piece metal or plastic fastener. The "top of the prong snap button" is typically the Cap or Prong Ring, which features sharp metal teeth (prongs) that pierce the fabric. 

The 4 Parts of a Prong Snap
A standard prong snap set consists of the following components: 
  • The Top Parts (Male side):
    • Cap / Prong Ring: The visible top decorative piece. It usually features an open ring with prongs or a solid dome.
    • Socket: The female component that interlocks with the stud. It sits securely behind the fabric layer linked to the cap.
  • The Bottom Parts (Female side):
    • Stud: The raised middle component that snaps into the socket.
    • Bottom Prong Ring: The piece that secures the stud to the back of your fabric.
How to Refer to the Top Piece in English
If you are looking for specific types of top pieces in English for sewing or manufacturing, use these exact terms: 
  • Open Prong Ring: A piece with visible sharp teeth surrounding an open center.
  • Pearl / Capped Prong Ring: A top piece covered by a smooth cap, painted finish, or faux pearl.
  • Solid Cap Snap: A classic riveted snap often found on heavy jackets.
If you tell me what type of garment or fabric thickness you are working with, I can recommend the ideal size and prong length for your snap buttons.