From The Art and Popular Culture Encyclopedia
The mythology and legends of many different cultures include monsters of human appearance but prodigious size and strength. "Giant" is the English word commonly used for such beings, derived from one of the most famed examples: the gigantes of Greek mythology.
In various Indo-European mythologies, gigantic peoples are featured as primeval creatures associated with chaos and the wild nature, and they are frequently in conflict with the gods, be they Olympian or Norse.
There are also other stories featuring giants in the Old Testament, perhaps most famously Goliath. Attributed to them are superhuman strength and physical proportions, a long lifespan, and thus a great deal of knowledge as well.
Fairy tales such as Jack and the Beanstalk have formed our modern perception of giants as stupid and violent monsters, frequently said to eat humans, and especially children. However, in some more recent portrayals, like those of Roald Dahl, some giants are both intelligent and friendly.