In physics, position as a function of time is generally called $d(t)$ or $s(t)$. Using "$d$" is pretty intuitive, however I haven't been able to figure out why "$s$" is used as well. Is it possibly based on another language?

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    $\begingroup$ it could be based on the german word 'Strecke', but I don't think this convention is that strict in the first place. $\endgroup$
    – luksen
    Commented Feb 23, 2012 at 18:41
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    $\begingroup$ Yes, $s$ stands for the german word Strecke, and $d$ for distance. $\endgroup$
    – Qmechanic
    Commented Feb 23, 2012 at 18:45
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    $\begingroup$ I prefer r(t) for position (i.e., instantaneous displacement from the reference point), to distinguish it from displacement (change in position over a time interval) s(t) and from distance travelled d(t). $\endgroup$
    – ryang
    Commented Oct 14, 2020 at 10:08
  • $\begingroup$ Do we know what is origin of usage of 's' as a "Strecke", i.e. who started using it or when? 100 years ago? 200-300 years ago? 500 years ago? 2000 years ago? Etc. $\endgroup$
    – Kusavil
    Commented Feb 9, 2023 at 14:18

1 Answer 1


As commenters have pointed out, it's German Strecke.

Note that $s$ is for displacement, whereas $d$ is for distance. Distance is the distance along the path traveled by a body, whereas displacement is the birds-eye distance traveled. Displacement can also be negative in 1-D, depending upon your reference positive direction.

For some reason, even though Strecke actually means distance, not displacement, its symbol is used for displacement.

You might want to check out this paper, it's got an analysis of the naming, mainly for electrodynamic units. A few symbols from the table at the end of the paper: $c$ (speed of light) comes from Latin celeritas; $I$ (current) comes from "intensity of current" in French (intensite du courant). The $\mathbf{A}$-potential, $\mathbf{B}$-field, $\mathbf{H}$-field got their symbols from the alphabetic order of the others.

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    $\begingroup$ Community wiki as I'm just answer-ifying the comments. $\endgroup$ Commented Feb 24, 2012 at 1:24
  • $\begingroup$ Comment to the answer(v1): Note that Strecke and distance usually denote non-negative quantities, while a displacement is a relative change in position, and therefore can be both positive and negative. $\endgroup$
    – Qmechanic
    Commented Feb 24, 2012 at 1:34
  • $\begingroup$ I've added it, though you could have added it yourself. It's community wiki for that reason; I myself don't know much about it. $\endgroup$ Commented Feb 24, 2012 at 2:02
  • $\begingroup$ I thought it might have been a misreading of a lower case delta. $\endgroup$ Commented Jun 1, 2021 at 22:31

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