They were called Tasmanian “tiger” because of their stripes.

However an early ship visit to Tasmania (then named Van Diemen’s Land) found footprints with long claws and the crew reported, basically, “here must be tygers!” It’s now accepted those tracks probably belonged to a wombat.

They were called Tasmanian “wolves” because morphologically they are quite similar to dogs or wolves.

They were called “hyenas” although it’s not clear why - maybe because their gait is loping and similar to that of the hyena; maybe because they were said to smell.

They were called “hyena opossum” - hyena, as above, and opossum because actually, marsupials were discovered by the Eurocentric world before Australia was. North America has the “opossum” (and South America has others). In Australia we have what are now called “possums” which are comparable to the North American opossum, but calling a Tassie tiger “hyena opossum” is another way of acknowledging it is a marsupial rather than placental.

Now it is popular to call them “thylacine”, after their taxanomic name - Thylacinus cynocephalus (wolf headed pouched thing), especially in more scientific write-ups, but “Tasmanian tiger” remains the most common Google search term for the species.