What were the heavily armed military order of infantry or foot soldiers of ancient Greece?

The were called hoplites (from the word hopla = a panoply - or full set - of arms and armour). They were not a military order, they were mostly just small farmers who turned out to protect their farms and city when needed. They assembled for training each month. The exception was Sparta, where they lived in a mess, trained regularly, but they had serfs to work their farms for them.