ORCAS The Finnish ppl call 'em WHALE KILLERS ('cause they kill Whales - they eat 'em alive!) "Killer Whale" is a mistranslation - the sentence structure is diff. Although related to Whales they're more similar to Dolphins!
Still not sure which word to use? Choose a picture and take a look through the many choices! This graphic has excellent pictures to go with the information and I think that really help gets the point across. Anna comments: expansion of vocabulary