「定規」と「物差し」の違いは何ですか


Can someone explain the difference?




  * 定規 = _straightedge_
  * 物差し = _ruler_

Now, consult an [English resource](https://www.reference.com/math/ruler-
different-straightedge-3f3fa91ce1e6d254) :)

> _The primary difference between a ruler and straightedge is that a ruler is
> a measurement device, whereas a straightedge is a tool for drawing or
> viewing straightness. A ruler is a straightedge with some scale on it so
> that it can act not only as a straightedge, but also as a device to measure
> distance. Therefore, a ruler is a straightedge, but a straightedge is not
> necessarily a ruler._

That said, practically all
[定規](https://www.google.co.jp/search?q=%E5%AE%9A%E8%A6%8F&tbm=isch) are sold
with measuring scale (which has no legal warranty), it's safe to say both are
synonyms in daily language.

cf. [compass-and-straightedge
construction](https://en.wikipedia.org/wiki/Compass-and-
straightedge_construction) = [ruler-and-compass
construction](https://en.wikipedia.org/wiki/Ruler-and-compass_construction)




  * 定規 = _straightedge_
  * 物差し = _ruler_

Now, consult an [English resource](https://www.reference.com/math/ruler-
different-straightedge-3f3fa91ce1e6d254) :)

> _The primary difference between a ruler and straightedge is that a ruler is
> a measurement device, whereas a straightedge is a tool for drawing or
> viewing straightness. A ruler is a straightedge with some scale on it so
> that it can act not only as a straightedge, but also as a device to measure
> distance. Therefore, a ruler is a straightedge, but a straightedge is not
> necessarily a ruler._

That said, practically all
[定規](https://www.google.co.jp/search?q=%E5%AE%9A%E8%A6%8F&tbm=isch) are sold
with measuring scale (which has no legal warranty), it's safe to say both are
synonyms in daily language.

cf. [compass-and-straightedge
construction](https://en.wikipedia.org/wiki/Compass-and-
straightedge_construction) = [ruler-and-compass
construction](https://en.wikipedia.org/wiki/Ruler-and-compass_construction)

