The term 'Small Whale' can be broken down into two crossword solutions: SEI (3 letters) and DOLPHIN (7 letters). The SEI is a species of baleen whale found in the North Pacific Ocean, and is one of the fastest whales in the world. The DOLPHIN is a marine mammal that is closely related to whales and porpoises, and is found in all oceans around the world. Both the SEI and the DOLPHIN are considered small whales, as they are much smaller than other species of whales.