Cursor
This is a general term for “placeholder.”
Here’s how we got to this definition, from Wikipedia:
In computer user interfaces, a cursor is an indicator used to show the current position for user interaction
Cursor is Latin for “runner.” A cursor is a name given to the transparent slide engraved with a hairline used to mark a point on a slide rule. The term was then transferred to computers through analogy.
So, a “cursor” is that clear plastic piece that slides along the length of a slide rule. I don’t know how a slide rule works, but I understand that was used as a placeholder.
Why I Looked It Up
I was working on some code that would export records from a database. Because of the particular architecture, I couldn’t export them all at once, and had to keep making requests for 200 at a time. This meant my code had to remember “where” I was at in the dataset, so I didn’t re-request records that I already had.
I remember thinking, “This is what they call a cursor in relational databases…”
Then I got to wondering where that name came from. I actually made the mental leap myself that “cursor” must mean placeholder of some kind, because that’s what the mouse pointer is on a computer screen – it’s a placeholder for whatever you’re doing.
So, I looked it up.
Postscript
Added on
In Hidden Potential, there’s a discussion of the origin of the word:
[…] cursor derives from the Latin currere, “to run,” and sometimes translates to “running messenger”, or “errand boy.” It was originally the name for a part on the slide rule – the piece that moves back and forth – and some computer pioneers borrowed it.