When school leaders use vague and inconsistent terminology, they often leave teachers confused about what they’re supposed to do and why.

Recently, over the course of a two-hour meeting, I heard the members of a school leadership team describe students as “on task,” “engaged,” “fully engaged,” “actively engaged,” “participating,” and “actively participating.”

When they used these words, everybody nodded their heads, suggesting that they understood each other well enough. But when I asked what exactly they meant when using terms like “on task,” “engaged,” and so on, they provided very different examples. In most classrooms, students seem to follow directions, one said. When teachers are talking, said another, lots of students nod their heads or raise their hands. When the bell rings, said a third, many students are reluctant to stop working on their projects.

When I visit schools, I often observe this kind of verbal imprecision, in which educators use a range of terms to refer to things that look to be sort of similar to each other. To many teachers and administrators, it seems, it’s OK to be vague when talking about student behaviors (or teaching practices, or learning outcomes, or any other aspect of schooling). To my mind, however, that’s a real problem.

Education is not an exact science. There’s no one best way to teach U.S. history, for example. There’s no one best way to ensure students come to school on time or to nurture students’ love of math. But if we lack a clear consensus about some things that go on in schools, that doesn’t mean we can tolerate a lack of clarity around everything. We can’t let gray language and nebulous definitions seep into every crack and crevice of the school building.

One might argue that it doesn’t matter all that much what we call things. (I say to-may-to, and you say to-mah-to. What’s the big deal?) But understanding what goes on in schools is much more difficult than making sense of tomatoes. If we want to provide high-quality educational practices and hold ourselves accountable to professional norms, then we need to be exceptionally clear about what we’re trying to do.

Recently, I witnessed a principal share notes with one of his teachers after observing her class. During the debrief, he kept referring to both the teacher and the students as “leaning in.” He’d say, “You’re really leaning in, so your students are leaning in as well,” and the teacher kept nodding in agreement. But when I asked them what “leaning in” meant, they became tongue-tied. Neither one could define the term.

In schools, we need to be exceptionally clear about what we’re trying to do.

To avoid sending mixed messages (or mistaking mere head-nodding for real agreement), school leaders should define key terms, share those definitions widely, provide clear models for and illustrations of success with those practices, keep parents and students informed, and ensure that everybody’s speaking the same language. All too often, though, school leaders speak in generalities, using education buzzwords that give people only a rough sense of what they mean. For example, when they use a half-dozen synonyms for “objectives” or waffle about how to share those objectives with students, teachers can easily come to believe that these things don’t really matter. If they did, then wouldn’t they be crystal clear?

If they’re not careful, school leaders can sow confusion on both a small scale and a large one. They can give imprecise feedback to an individual teacher, leaving her unsure how to improve her performance. And they can also roll out a new school initiative in a way that gives 50 teachers 50 different impressions about what the initiative aims to accomplish, why it’s being rolled out, and what it will involve. Of course, leaders themselves may not be entirely sure how individual teachers can improve or what they want their new initiatives to achieve. But, in that case, they can at least clearly communicate what they’re unsure about. Wandering from one ambiguous term to another only amplifies the uncertainty, creating extra noise in the already very noisy world of K-12 education.