What does modernity mean?
A visit to Dictionary.com tells us that the definition of modernity is "the quality of being modern." This definition is only so helpful unless we consider what it means to be modern.
In the humanities, we refer to modernity in terms of certain cultural shifts that began with the European Renaissance and spread throughout the world during and after European Imperialism. We consider the Modern Period to have begun in different times in different places, and some parts of the world might be said to still not have entered the Modern Period. So, what do "modern" cultures have in common that defines them?
Modernity implies an emphasis on that which is empirical, quantifiable, logical, or based in reason. This is in opposition to understanding the world and acting based on a sense of tradition or qualitative impressions. Cultural shifts like the Age of Discovery (for the sciences) and the Enlightenment Period (for philosophy) have helped to shape societies which value objectivity and that which can be measured and demonstrated over a subjective, perceived experience.
It can be a little hard to wrap our heads around such a concept without an example, so let's compare two port cities-- one established in the Pre-Modern Period, and one in the Modern. If you click here, you can view a map of Dublin, Ireland. Notice how the streets seem to radiate out from the center of the port. Development of the area surrounding Dublin began during the Pre-Modern Period, and people naturally gravitated towards the center of where business could be done. Settlement patterns in the Pre-Modern Period were largely based on where people felt was a good place to be. In comparison, have a look at this map of New York City, which has been developed in the Modern Period. Notice how the streets of Manhattan have a far more organized, grid-like pattern. Can you see how an emphasis on order, logic, and quantifying space has helped to shape the layout of the City? Take note of the high degree of consistency in the shape and size of segments of the city. Much of Manhattan was planned and developed in expectation of population growth. In contrast, Dublin was developed as a result of population growth.
I don't mean to imply that one form of city planning is inherently better than the other, but I hope that this example helps you understand how Modern values have come to shape our lifestyles in addition to ways of thinking.
In other aspects of culture, like education and the arts, we find that modernity implies a break with tradition and/or collectivism in favor of individualism.