hondata is chipping a stock ecu. engine management is anything that controls the function of the engine, fueling, timing, etc.

hontata is a stock ecu that is modified to adjust/scale the stock parameters and/or add others. crome, uberdata, ectune, neptune, etc do the same, but in different ways. aem, motec, etc are standalone engine management ecu that do the same thing, but with their code, not honda stock code.