levure de boulanger: yeast, sold either frais (fresh) or dried (levure sèche du boulanger traditionelle) which needs to be activated in warm water for 15 minutes before use. Levure instantanée or action express is ready to use without the delay.
levure chimique: baking powder. It comes in little paper sachets of 11 grams in France, good from 500gr of flour for most recipes. Also known as poudre à lever or poudre à pâte.
levure de bière maltée: brewer’s or nutritional yeast
levain: sourdough starter
Image by Hellahulla