Golpe is mostly used in Flamenco guitar. It is a finger tap on the golpeador ("pick guard").
Technique
It is usually performed with the middle or annular (ring) finger, and can be performed either simultaneously with a down-stroke performed by another finger (e.g. simultaneous down-stroke with index finger and golpe with annular finger), or independently in order to accent off beats.
This technique requires the strumming finger and the golpe finger to move in opposite directions at the same time.
References
Golpe (guitar technique) Wikipedia(Text) CC BY-SA