Ether/ˈiːθər/ Definition 1 of 4Pro Tip 1/2Chemistry Use Remember that 'ether' in chemistry refers specifically to a group of organic compounds. The lab smelled of ether used for extractions. Pro Tip 2/2Safety Precaution Be aware when discussing ether in chemistry; it’s known for being highly flammable. Store the ether away from any heat sources.