Confused about modes in music theory? They're actually really simple.

A mode is when we take the notes of a scale, usually the major scale, and establish a different one of those notes as the tonal centre. For example, in C major, we usually begin and end on the note of C, and establish C as the tonic. What if we were to take the same notes from that scale, but use one of the other notes as the tonic? That would be a mode.