The pentatonic scale is very popular amongst guitarists, especially the first shape. The position of it makes both the lower and higher notes on the fretboard easily accessible.
This particular shape is called the A minor pentatonic scale shape 1 (there are 5 different shapes). The name of the scale (A) comes from the fact that the very first note of this scale is A (the 5th fret on the 6th string is A). The minor part of the name is related to the sound this shape creates.
So basically the A minor pentatonic scale shape 1 means that we are starting this scale from the note A and it is going to sound like a minor scale. The great thing about the pentatonic scales is that they always have two notes on each string – which makes it easy to memorise (especially shape no.1).