Refers to a large cork or stopper, often used in a figurative sense.
Necesitábamos un taponazo para cerrar la botella de vino que habíamos abierto.
We needed a big cork to close the bottle of wine we had opened.
El taponazo de la botella sonó fuerte, sorprendiendo a todos los presentes.
The big cork from the bottle popped loudly, surprising everyone present.