The right definitions :
1. Molecular Gastronomy : the science (mostly chemistry and physics) that explores the mechanisms of culinary transformations, producing knowledge (see also my article in the Encyclopedia Britannica) ; this is "philosophy of nature", or natural science ; it does not produce food!
2. Molecular Cooking, or Molecular Cuisine : a way of cooking that uses "new" tools, ingredients and methods. It was a way to propose a modernization of the culinary techniques
3. Culinary Constructivism : building dishes so that a particular effect is reached. It's again cooking
4. Note by Note cooking : it means "cooking with compounds" (and in the right idea of this, the compounds, or ingredients, should be "pure", ie of only one kind, such as sucrose, water, glucose, ethanol, tartaric acid, citric acid, etc.)
Hope that helps!