CSS Specificity
I was recently asked to define the term "Specificity" as it applies to CSS. Though I was very familiar with the process of how a browser determines which set of CSS rules will take precedence when multiple rules are applied to an object, I was unfamiliar with the term. Looking back on it now the term seems obvious, but when put on the spot I didn't have time to analyze the word to determine the meaning. That and I wouldn't have felt comfortable guessing. Immediately after being asked the question I did a quick Google search and slapped myself on the forehead for not being familiar with the term.
I did however find a brilliant post by Andy Clarke over at stuffandnonsense.co.uk/archives/css_specificity_wars.html. Andy even created a great little chart that illustrates how browsers calculate specificity using Star Wars characters. I encourage you to check it out!
Never underestimate the importance of not only knowing the skills of your trade, but also knowing the terminology that applies. ;)