"Multiple stops", or specifically, "double stops", "triple stops", etc. Borrowed from orchestral string terminology. Wonder why the 'stop' word is used. It hints at notes being fingered, but also is used when open strings are played simultaneously.
What is it called when several strings are played at once?
In music, a double stop is the technique of playing two notes simultaneously on a stringed instrument such as a violin, a viola, a cello, or a double bass. On instruments such as the Hardanger fiddle it is common and often employed. In performing a double stop, two separate strings are bowed or plucked simultaneously.
What is hybrid picking guitar?
Hybrid picking is a guitar-playing technique that involves picking with a pick (plectrum) and one or more fingers alternately or simultaneously. Hybrid picking allows guitar players who use a pick to perform music which would normally require fingerstyle playing.