I knew the first two definitions,  but not the third.  Neat.

@Myr Great choice of using the word phalanx in a sentence, along with the gif. 

The arrival of the Greek phalanx was a rude shock on the battlefields of the classical period. It imposed tight discipline and teamwork their contemporaries could not match. Alexander the Great conquered the known world with the phalanx. Given the metallurgy of the time, nothing could stand against it until the Romans arrived with their shield wall and iron weapons.

You may have noticed in Peter Jackson's treatment of Tolkien's The Hobbit, in the Battle of the Seven Armies, the Dwarves of the Iron Hills used a form of the phalanx.