On Grinds
When I moved to Ireland a couple of years ago, one of the words I discovered had a usage with which I was unfamiliar was grind. My first encounter with this word was after a lecture on vector calculus when a student asked if I knew of anyone who could offer him grinds. I didn’t know what he meant but was sure it wasn’t the meaning that sprang first into my mind so I just said no, I had just arrived in Ireland so didn’t know of anyone. I resisted the temptation to suggest he try finding an appropriate person via Grindr.
I only found out later that grinds are a form of private tuition and they are quite a big industry in Ireland, particularly at secondary school level. School students whose parents can afford it often take grinds in particular subjects to improve their performance on the Leaving Certificate. It seems to be less common for third level students to pay for grinds, but it does happen. More frequently university students actually offer grinds to local schoolkids as a kind of part-time employment to help them through college.
The word grind can also refer to a private tutor, i.e. you can have a maths grind. It can also be used as a verb, in which sense it means `to instil or teach by persistent repetition’.
This sense of the word grind may be in use in the United Kingdom but I have never come across it before, and it seems to me to be specific to Ireland.
All of which brings me back to vector calculus, via Charles Dickens.
In Hard Times by Charles Dickens there is a character by the name of Mr Thomas Gradgrind, a grimly utilitarain school superintendent who insisted on teaching only facts.
Thomas Gradgrind (engraving by Sol Eytinge, 1867).
If there is a Mr Gradgrind, why is there neither a Mr Divgrind nor a Mr Curlgrind?
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In the Dark 
July 24, 2020 at 1:58 pm
I think it still does have the meaning in English of intense learning or work, i.e., ‘working through chapter 2 is a bit of a grind, but worth it’
July 24, 2020 at 4:44 pm
Yes; or equally, “There is no slick shortcut in the derivation of this result; you just have to grind it out.”
July 24, 2020 at 2:21 pm
The del operator is vectorial but in Clifford algebra it can be applied to anything. Dot it with a vector and it is called grad; cross it with a vector and it is called curl. I suppose that grad is its name when applied to a scalar to give a vector, but if you allow grad to be synonymous with del then you have an answer to your rhetorical question. Furthermore in Clifford Algebra you can add the dot and cross products of del applied to a vector, even though you are adding a scalar and a vector. It’s no different from adding a real and an imaginary in complex analysis – in fact it is the 3-dimensional generalisation, and as superior in 3D as complex analysis is to 2D vector analysis. You can generalise it to arbitrary dimension, in fact.
July 24, 2020 at 2:30 pm
I’d be interested to know how del and nabla are distributed, both geographically and across disciplines. As far as I’m aware they are different names for the same symbol.
July 24, 2020 at 6:33 pm
Perhaps an age-related thing? When I studied a course on vector field theory back in 1976, the lecturer (a professor probably in his 50’s at that stage) called it nabla. So did I when I lectured the course in 1990 ! Suddenly it became del …
July 24, 2020 at 8:44 pm
Perhaps a transatlantic thing? I also wonder what it is called in other languages.
July 24, 2020 at 8:49 pm
It’s \nabla in Latex…
July 25, 2020 at 4:15 pm
It is nabla in Scandinavia and, i think, in German. The physics student society in Trondheim is called Nabla. (Its AGM is the Grand Canonical Ensemble.)
July 24, 2020 at 4:45 pm
Gah, I meant “div” where I first wrote “grad”!
July 24, 2020 at 9:52 pm
A rotgrind would be the best.