Defining the perimeter of our parameters
The Monitor’s language columnist is forced to come to grips with two words related to measurement.
I've put it off as long as I could, but I knew I finally had to confront the task: getting my head around parameter.
When I've run across the word, I've interpreted it as something akin to "aspect" or "dimension," and let it go. But I know that some experts sniff at those who use it loosely, without quite knowing its meaning. Hmm, let's not be one of those.
But I often have to confront as an editor words I can avoid as a writer. Parameter turned up in a book I was editing.
Parameter comes from Greek words meaning "beside" (as a paralegal, for instance, works beside a lawyer) and "measure." It was originally a term in geometry. Noah Webster defined it thus in 1828 – I'll quote, because I dare not paraphrase:
"1. The latus rectum of a parabola. It is a third proportional to the abscissa and any ordinate, so that the square of the ordinate is always equal to the rectangle under the parameter and abscissa; but in the ellipsis and hyperbola it has a different proportion.
"2. In conic sections, a third proportional to any diameter and its conjugate. In the parabola, a third proportional to any absciss and its ordinate."
Got that? I'm not sure I do, not even after studying the diagrams I found online. By the 1920s, though, parameter had come to refer to a "measurable factor" that helps define a "particular system."
And that's how my text was using it: "A parameter is one of the things we test for."
By the 1950s, what the Online Etymology Dictionary calls "the modern meaning" of boundary, limit, or characteristic factor had taken hold.
And this sense was influenced by another term with Greek roots, perimeter. "Peri" means "around." In the 1590s, a perimeter was a line around a figure or surface. By World War II, the word had a military sense: "boundary of a defended position."