The term "Renaissance" literally means "rebirth." The Renaissance refers to the period in Europe beginning in the 15th century CE. It followed the Middle Ages, which began after the fall of the Roman Empire in the 5th century CE. This marked the end of ancient history and the Classical Period.

The Renaissance is characterized mainly by the rediscovery of ancient philosophy, art, and science, which had been neglected or censored in the Middle Ages. It therefore ushered in a period of great accomplishments in these areas. The change from the Age of Faith to the Age of Reason is a hallmark of the Renaissance.

Typifying the Renaissance is the great Leonardo Da Vinci. His accomplishments in science and art are legendary. He did incredible work with the study of the human body as well as developing weapons of war. His Mona Lisa and Last Supper are among the great works of art. Leonardo was a true "Renaissance man" as he typified the humanistic, scientific, and artistic characteristics of the period.

The Renaissance, particularly in its origins in Italy, was characterized first by a new commitment to the spirit of humanism. Humanism was, essentially, based on the study of the classics, both the Greeks and the Romans, and it was framed by Renaissance thinkers as a way of breaking away from what they thought of as the "dark ages" of medieval Europe. Almost all of the important Renaissance writers, including Machiavelli, Pico Della Mirandola, Lorenzo Valla and Leonardo Bruni wrote within the humanist tradition.

Renaissance thinkers also stressed individual achievement, especially in secular pursuits. For the first time since Roman times, artists and architects were viewed as public figures who should be celebrated, and individuals were measured by the breadth of their accomplishments. The "Renaissance man," was, simply speaking, good at everything, and this was something to be pursued not just for the glory of God, but as a means of achieving fame and fortune. It was in this context that learning about the world through observational science first became a major emphasis.

Finally, the Italian Renaissance was characterized by great artworks that emphasized balance, proportion, and harmony. All of these principles had been important in the classical world, but were largely neglected during the Middle Ages. The achievement of these ends demanded a high degree of technical skill on the part of the artist.

What were the major characteristics of the Italian Renaissance?

During the late 14th century and into the 15th century, Italy emerged from the Dark Ages into a period of rebirth, referred to as the Renaissance. One of the characteristics of this age was renewed interested in classical texts from Greek and Roman antiquity. From these texts, Renaissance thinkers renewed their interest in humanism, or the importance of humans in the world. The belief in humanism affected many fields, including art, which began to focus on the beauty of the human form.

Humanism led to another characteristic of the Renaissance— questioning religion. As thinkers began to conduct scientific inquiries using observation and investigation, technology began to develop. In addition, Renaissance figures such as the artist Leonardo Da Vinci studied the human form and produced detailed studies of human anatomy that were important to medicine. Da Vinci was, in fact, the true Renaissance man—a term we use today to describe people who are good at a number of fields and who are motivated by an interest in everything that is human. 

I think the biggest characteristic of the Renaissance to highlight is the emphasis on humanism.  Humanism (very simplified) is the belief that humans have potential and are valuable - versus the previous era's belief that the afterlife was the only real important thing.  Humanism placed much emphasis on reason instead of relying strictly on the church for explanations.  This is best exemplified by Da Vinci's sketches of the human body... instead of just relying on the church to explain how the human body works, he took it upon himself (embodying the humanist spirit) to dissect and explore the human body... he was accused of necromancy (worshipping the dead) because of it!!

Hmm. The major characteristics of the Italian Renaissance? A big question. I'd say the following:

1) A rediscovery of classical learning (that's the re-birth of the name)

2) An emergence of humanist attitudes

3) An infusion of sciences, some of which were original and some of which came through trade (such as with Islamic scholars)

4) An explosion of the arts. (Think Michelangelo and da Vinci.)5) Within Italy, a focus on active politics, include city-state politics6) A collapse of older medieval society, in part due to the Black Plague