Why are t rex callwd t rex?

Answer 1

The word is derived by joining two Greek words together, as happens a lot in scientific names. The words are dino- from 'dienos' (powerful/terrible/fearful) and saur from 'sauros', a lizard. (source: A Dictionary of the Roots and Combining Forms of Scientific Words. Tim Williams)

At the very beginning, it comes from two Greek words meaning "terrible lizard", When they were first discovered, their large size made scientists believe that these reptiles were terribly fierce creatures. (Source, world book student dictionary)
The word dinosaur can be broken into 2 greek roots. The root deino which means terrible, and saur which means lizard. So the word dinosaur means terrible lizard.

Answer 2

The Mesozoic is called the Age of Dinosaurs because all dinosaurs, except birds, lived during the Mesozoic. During that time, dinosaurs were the primary, large terrestrial animals on all seven continents.

Answer 3

The word means "thunder lizard"

It was assumed - probably correctly - that a big dino would make a lot of noise when it stomped by.

Answer 4

Because they are reptiles that lived before history was recorded.

Answer 5

The meaning comes from the Greek words meaning 'tyrant and lizard'

Answer 6

Because they died long ago