Modernity is the quality of being modern — new ways of living, thinking, and making things, as against old or traditional ones. In everyday talk people more often say “being modern” or “modern life.” Modernity shows up in essays and history books. There it can mean more than a fashion: cities, factories, science, clocks, and the idea that the future should not copy the past. Though actually, university writers argue a lot about when modernity began and whether we are still inside it. You may later meet late modernity or postmodernity; those are extra labels, not extra meanings you need for this word. The simple heart is “modern-ness.” It is a noun, not an adjective.