Kaizen, Kaikaku, Kakushin
Kaizen - Japanese word for 'change for better', it refers to incremental improvements at work place. Most popular methodology for Kaizen is Quality circles or Small Group Activities
Kaikaku - Japanese word for 'radical change' refers to a larger revolutionary change. It could be an enterprise wide ranging project, that brings in a large savings or improvement to the process or product
Kakushin - Refers to an 'innovative or a transformative' change which will result in complete departure from the current situation. It could be a total newly conceptualized product or a market disrupting process / service
An application oriented question on the topic along with responses can be seen below. The best answer was provided by Venugopal R on 7th September 2017.