The definition of "Gestalt" under Ehrenfels and Fritz Perl is
The perceptible space-form of objects; assigned as well to psychic and historic-cultural things:
In a similar manner, heuristics constitute the rules of thumb, the chosen methodology, or the preferred manner in which we select to group or categorize persons, places, and things based on a composite of most salient terms.
In this manner, heuristics and Gestalt represent two cognitive skills that individuals use to put into practice the analytical, inductive, and deductive skills that lead us to make choices and problem-solve. In both processes, one needs to use perception, close observations, schema, historical and cultural data, and previous experiences to better understand and identify something.
More definitions of Gestalt include:
Things, whose parts are determined out of the whole, in which all parts carry and condition each other; things, whose essential qualities can't be grasped by summing up the qualities of the parts;
Like when using heuristics, Gestalt implies the separation and observation of salient traits that tend to repeat themselves under different circumstances and tend to form a construct of the origin and category of a person, place, or thing.