Well, it isn't a word we use every day, especially since there isn't really an English equivalent
In psychology, it basically means that we perceive, interact with, and relate to the "whole" of an environment, situation, stimuli, etc rather than individual components
I guess an example would be an A&M football game. What you experience isn't blades of grass, alloys in band instruments, each game ball, spectators, a jersey, etc. your takeaway is the whole game day experience. Yeah you may take notice of a players' shoe, or whatever, but your experience is the whole "Aggie game", rather than a collection of tiny components. It's the relationship formed by the components, rather than components themselves
Simply, your Aggie game experience is the "big picture", rather than a million "little pictures"