Pallas

Pallas is in fact two separate and distinguishable names. The first Pallas (genitive Pâllantos) was a Titan, the son of Crius and Eurybia. The second Pallas (genitive Pallâdos) was the goddess Athena, for whom it was the best-known by-name (often used together with Athena, as Pallas Athena, but later used alone).

The first Pallas (and various others of the name, including according to some accounts even the father of Athena) has a name that may mean simply 'young man' (pallas) or perhaps 'shaker', 'brandisher', from pallo, 'to wield', 'brandish'. Either meaning would be suitable for a giant. The second and more famous Pallas has a name that is variously explained.

Some of the theories proposed are as follows.

1. That it was borrowed from the Titan Pallas as a 'powerful' name. (But, as mentioned, this is actually a different name.) 
2. That it derives from the blow struck by Athena when she killed this Titan - or from some other blow (from pallo, 'to wield', 'brandish', 'leap', as for the Titan Pallas). 
3. That it refers to the spear that she constantly flourished, and which she was brandishing even at the moment when she was 'born' by springing forth from the head of Zeus that Hephaestus had split open with an axe (pallo again). 
4. That it refers to this actual blow by Hephaestus which enabled Athena to be born. 
5. That it was taken in memory of a playmate of this name, a daughter of Triton, whom Athena accidentally killed as a girl. 
6. That it simply means 'young maid' (palla), just as pallas can mean 'young man'. (Compare Latin puella, 'girl'.) Of all these possibilities, it is generally reckoned that the last explanation is the most likely.

We also need to connect her name with the Palladium. This was a legendary statue of Pallas Athena, said to have been dropped down from heaven by Zeus to Dardanus, the founder of Troy, to ensure the city's protection. According to Virgil it was stolen by Diomedes and Odysseus, as a result of which the city was burned down.

The London theatre called the Palladium seems to have been so named as the result of a misunderstanding: perhaps it was thought that the Palladium was not a statue but a type of theatre or circus like the Colosseum (which word may have confused the issue). The Colosseum, of course, was not even in Greece, but was the great amphitheatre at Rome, and far from mythological.