You’ve probably heard it more than once, “That new development has too much density” or “Vancouver has the second highest density in North America”, but what do people mean when they invoke “density”? Thankfully, The Conversation has taken the time to break down the various interpretations (and misinterpretations) of density. From population density (typically measured as residents per hectare, based on census data) and overcrowding to building height and floor area ratio (or floor space ratio, or floor space index) there are many different interpretations. While each definition has purpose, the vital factor is to ensure that everyone in the conversation understands and uses the same measure. As with many other aspects of city-making, communication is key.