Relevant and pertinent both mean related to or mattering with respect to the case at hand. Relevant suggests something is related to, or has bearing on, a topic or situation, and hence is useful or appropriate: Please explain how the facts you cite are relevant to the topic. Pertinent keeps company with many of the same nouns as relevant–question, point, fact, and information, for example–and the two words can be strong synonyms. We tend to use relevant when the question is whether something simply is or is not relevant, whereas pertinence suggests a positive degree of relevance. Something pertinent relates directly and significantly to the exact matter at hand (Include background only if it’s pertinent and to the point.). It appears frequently with the adverbs particularly and especially, which reinforce its meaning.

On this International Cat Day, we look at a distinction of the utmost importance, the difference between dozing and sleeping. To sleep is to be in a state of deep rest in which consciousness is suspended (the viral video of a kitten sleeping flat on its back), or to regularly enter this state for an extended period (She sleeps in the spare room.). Doze implies being lightly asleep (I'm not asleep; I was just dozing. Cats hear everything while they doze.), or slipping in and out of a light sleep (doze in front of the television on Sunday afternoon). When we unintentionally fall into a light sleep, we often say we dozed off, and when we're surprised or confused about having been asleep, we say, “I must have dozed off!”

Empty and vacant denote absence of content or contents. Empty means without the appropriate or usual contents: an empty refrigerator; empty bottles. An empty room could be a bare room or one without people in it (the theater was almost empty). Vacant is usually applied to that which is temporarily unoccupied: a vacant position; three vacant apartments. A vacant lot is a piece of property which has no buildings on it and lies unused.