She walks in and throws up her hands in a gesture of frustration. 

“Now we are doing circle stuff, like area.  There’s this thing he kept talking about today in class, like…it’s in the circle, it’s like…important in the circle.”  She puts her head in her hands.  She sighs. 

She explains she doesn’t even know what it is but in any case she doesn’t get it.  Apologizes to me for “doing a bad job of explaining.”  Oh sweet baby girl.  It’s not your job to teach yourself no matter what they tell you.   

There’s a thing and it’s important in the circle.  Let me tell you something right now. Very few people or actually no one will remember all the content but she’ll never forget how you made her feel in class today.  Do you want to know how you made her feel in class today?  You made her feel head in hands.  She’s so little still.  Why are you making her feel head in hands?  Last week you asked them to solve variable proportions and to derive linear equations from graphs.  At the same time.  For reasons that remain unclear but are likely connected to either your total inability to understand how math works or the fact that you like to torture children, IDK which man and I’m tired of both emailing you and guessing. 

I’m not here to judge you but I do have to clean up your mess every week so don’t hate me for speculating. 

First I will make you a cup of tea, child, and then I will start at the beginning.  It’s not your job to remember all these things.  It’s your job to think. Learning does not go in a straight line.  You probably won’t remember everything I am about to tell you.  We’ll need to circle back to this circle stuff.  That is normal and okay.

The origin of a circle is called the center.  It’s supposed to be marked and labeled as a point but they don’t always do that.  They aka the People In Charge of Things.  The people in charge of things you have to put up with starting from now until you die. These things range from this stupid math curriculum to what you are legally allowed to do with your own female body. 

I don’t say the last part but I think it.  I think about that last part a lot as I watch my girls turn into women before my eyes.  Everyone says it happens so fast. Everyone is right.

Once you understand that every circle has a center you can feel grounded in the next term, which you absolutely must have your picture for.  The next term is “radius.”

I say “radius” and her eyes light up.  YES EMILY.  YES.  THAT’S THE THING THAT’S IMPORTANT IN THE CIRLCE.  I laugh.  Okay so but like what does radius mean, though, young woman?

Because you are only going to be able to work with something if you know what it means.  What do you notice about the spelling?  Do you see anything at all?  Take your time.  We are not in a hurry. 

She notices there’s probably not a prefix.  Well done.  She knows every word in English either has a base or is a base so that’s also helpful to verbalize, which brings her to the suffix.  Is there a suffix?  She thinks there might be, and I can tell she is already noticing that if there is an analyzable suffix in the construction “radius” it’s non-productive, meaning we can see the Latinate bones and we can analyze them but no native English speaker is going to be able to form a new lexical item from them. 

Sometimes all you can do is look at the bones.

I congratulate her for being both a scholar and a lady.  She beams. 

She’s noticing that <us> in radius for a really good reason.  She can see the bones.  This kid spots the default Latinate connecting vowel letter faster than I can put on pants, and once you notice something true it starts to stand out.  I explain that there is a classical <us> suffix, just like there’s a classical <um> suffix. 

We haven’t even looked it up yet.  For whatever reason we’re both in the mood to savor just sitting with this word for a moment.  No reason to rush off right away.  I’m not here to pound terminology in.  If I can get her to make a picture for this word she’ll be in business and that my friends is the goal.   

Get your picture first.  Just like when they tell you on the airplane to put on your own oxygen mask first before assisting other passengers.  You’re of no use to anyone if you are trying to do a thing while suffocating. 

Breathe first, do second.

By the time we get to Douglas she is ready to notice more things.  She zeros in on the Latin.  It’s the same as the English, she says smugly.  Yes my dear.  It’s the same.  Isn’t that lovely?  We’ve seen this before: often math and science words are just plucked from Latin, gliding into English unchanged.  That’s why you are seeing that <us> suffix.  You’re so smart.  How did you get to be so smart?  You are the smartest girl.

She jumps up and writes “radius” on the board, next to my drawing of a circle with a clear center point.  She loves writing on the board. 

Let’s talk about what this word meant in Latin before we talk about what it means in English.  I don’t always go this direction when it comes to meaning, from Latin to English, but with this kid and these terms sometimes it helps.  The way it was used in Latin will inform how we understand it in English, especially in this context.  She comes back around to me so I can show her on Etymonline that in Latin the word radius meant, “staff, stake, rod; spoke of a wheel; ray of light, beam of light; radius of a circle.”

I get up and go up to the board without a word.  I gesture for her to watch.  I take a red pen and dramatically place the pen on the center of the circle like I am throwing a dart.  Now watch, I say, even though I don’t need to say that because she is a 1,000% with me.  I draw a firm, straight red line from the center of the circle outward to the circumference.

She smiles.

The radius radiates out from the center, my friend.  It’s an old old old word that has a collection of senses, but the mathematical sense has been with us for a very long time and for good reason.  It makes sense. 

We find a whole collection of words from the Latin radius, words like radiate, radium, radiation, radial, radio and ray.  I do a small yelp of pleasure when we find ray, with its evolutive derivation through French from the same Latin etymon.  Radius and ray, a pair of lexical doublets.  Woulda look at that.

Later I find the word radiolarian, which seems to be the scientific name for a type of tiny single-celled aquatic organisms.  Their spherical bodies seem to have spikes radiating outward; I spend far too long looking at the black and white images on Google.   

Days pass and I find myself in a jiu-jitsu class.  It’s my third class.  I’m fully getting my ass handed to me.  I have no idea what I’m doing and to make matters worse people are trying to choke me, which frankly feels remarkably like trying to run a one woman small business trying to help the dyslexics, so while I am deeply uncomfortable I also feel oddly at home. 

At least people are up front at jiu-jitsu.  In the rest of my waking life sometimes you don’t even know you are being choked until it’s too late.  At least at jiu-jitsu you can usually see it coming.

The thing about the radius is that it’s also a bone.  It’s one of the two bones in your forearm.  I realize in class that because I understand what radius means I thus understand what the radius does.  It rotates the forearm from the elbow joint.  Your job in jiu-jitsu is to neutralize and then control the movement of your opponent. 

I realize in class this is most effective if you understand where movement originates in the body. 

We are working on immobilizing the radius because if you do that then the forearm of your opponent cannot be used as a staff or rod against you any longer.  Pin their radius, control their light.  Learn words, understand life.  Breathe.  Learn alongside children.  Focus on truth.

Most of all?  Circle back.