The Importance of Vocabulary

Glaring truism alert!  Subject-specific vocabulary is extremely important. The right academic vocabulary turns a clumsy conversation into an elegant and precise one.

In mathematics we have the issue that certain words have a different meaning in common speech, take “roots” or “degree” for instance (degree has more than one meaning even in mathematics – the degree of a polynomial, degrees in a turn). We also have words that it is perfectly plausible to leave out of the curriculum, and that you will find many students never encounter (such as “commutative” or “subtrahend”). But how much better is it if teacher and student have a shared technical vocabulary, one which helps us to be mutually understood and to express ourselves unambiguously.

It can be tempting to avoid complex words with students, especially those who aren’t the highest-attaining, yet I’d argue that, in the pursuit of increasing attainment, all our students benefit when they can express themselves clearly and succinctly.

During lessons I reserve the rightmost side of my whiteboard for my Key Words column, where I write the mathematical vocabulary as we come to it. The students write it in their books, and whenever someone answers a question or explains their thinking in way which could be improved with one of the key words my response would be along the lines of, “you’re absolutely right, now how can you say that using the right word(s) from the list?” If they’re not sure, I ask someone else to help. By modelling the use of vocabulary and requiring students to say it themselves whenever possible I believe they are more likely to remember it.
It is also important, on the principle of spacing, to revisit previous technical words when you can to improve their retention. Before Christmas I was doing prime factor decomposition with year 7 and someone asked whether  the answer of 30 = 2 x 3 x 5 could be written in a different order. I opened it up to the class and someone said that it didn’t matter “because you can multiply numbers in any order and get the same answer”. I could leave it at that, but there is a better way to answer the question, so I asked the class, “and what do we call this property of multiplication?”  Some could remember the word commutativity“, but not all. Now they’ve been reminded though, so they are less likely to forget again, and next time the opportunity arises we will remind ourselves of the word, until it becomes their first answer.

All of the key vocabulary is in our knowledge organisers (which I am still working on but will share at some point) and I regularly get students to refer to these.  As an extra touch, we rotate difficult words as our passwords for programs, so the students are forced to learn their spellings (by hook or by crook!)

I have noticed a big difference in the ability of my students to explain their thinking and to understand what they read since doing this habitually and it extremely easy to implement in a classroom – good ideas often are.

N.B. If you have never read Teach Like a Champion by Doug Lemov please do so. The rationale behind increasing our focus on vocabulary like this came from the book, which is the best teaching manual I have read in more than a decade.



  1. Completely agree with this. I used to shy away from “technical” vocabulary thinking that it might distract from the underlying maths I want them to learn. But I’ve come to realise that these specific words are useful. And actually, I have been surprised at how many of my students enjoy learning them and using them. It makes them feel clever!

    Liked by 1 person

  2. I agree! I used to reinforce subject vocabulary by having them search for definitions in their textbooks. Now that we do most things online in my classes, I have switched to a digital glossary that includes diagrams – I find that students are more likely to link the word to the concept if they also have a visual. For their glossaries, they are required to draw their own visual (making them go through the process of representation, which further reinforces understanding). I’ll try and get a post written where I share how this works so it can be seen in full, as it’s hard to describe in a comment.

    I like how you keep a running list of vocab on the board, so it is constantly present and used during class discussion. I am sure this is particularly helpful for those who don’t have English as a native language (although many native speakers also struggle with subject-specific vocabulary). Thanks for the suggestion!

    Liked by 1 person

  3. Some (low-literacy) students feel intimidated with ‘long/complicated sounding words’. When we come across such a thing in lesson, I ask the class to say it all together, so they feel less unsure. It can almost feel therapeutic to be all chanting ‘frustum’, ‘hypotenuse’, ‘commutative’ etc…This simple step does make a difference, as does the (exactly right) ‘forced used’ of correct terminology…..


    • If we don’t ‘force’ its use then only a small number of students will actually use these words. I’m a great believer in requiring the things you want to see. Same goes for showing working in the way it’s been demonstrated.


  4. […] Important mathematical vocabulary is written up on the board and I expect it to be used in answers.  If someone gives an answer which could be better explained using a mathematical word, I ask them to improve their answer and guide them to the best words.  This is important because vocabulary will only stick if we use it.  By controlling periods of talking I can make sure my students are using the vocabulary I want them to become proficient with. […]


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