# Definition: Sinister --- "On the left?" **URL:** \ **Category:** Factual Questions\ **Created:** [November 24, 2023, 8:43pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649 "2023-11-24T20:43:29Z")\ **Posts on this page:** 6\ **Page:** 3
**Author:** ![Spice\_Weasel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spice_weasel/32/5435_2.png) [@Spice\_Weasel](https://boards.straightdope.com/u/Spice_Weasel)\ **Post date:** [November 25, 2023, 8:35pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649/41 "2023-11-25T20:35:31Z")
> [@Saint\_Cad](#): > > It is a small sample, but both my grandfather and Mrs Cad fall into that category and their sense of direction is worse than horrible. I was permitted to use my left hand, but I do have a terrible sense of direction. It’s hard to imagine it being worse. ---
**Author:** ![Limmin](https://avatars.discourse-cdn.com/v4/letter/l/f04885/32.png) [@Limmin](https://boards.straightdope.com/u/Limmin)\ **Post date:** [November 25, 2023, 9:05pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649/42 "2023-11-25T21:05:08Z")
Math definition: dextral = right-handed system, e.g., when you want to define coordinates for three dimensions. The first two dimensions, x and y, are defined following the usual cartesian coordinates, with x perpendicular to y. But which way does the z direction point? It’s usually defined using the cross product following the “right hand rule” in which the cross product of x and y is z. If z were to point the other way, it would presumably be a “sinistral” system. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [November 25, 2023, 9:12pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649/43 "2023-11-25T21:12:53Z")
Can you point in the general direction of the closest large city? If so you are much better than Mrs. Cad. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [November 25, 2023, 10:14pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649/44 "2023-11-25T22:14:38Z")
> [@kenobi\_65](#): > > I wonder if your right eye is your dominant eye. I’m right-handed, and my parents tell me that I never showed any inclination for preferring my left hand when I was a young child. I’m also right-handed but left eye dominant. I learned that somewhere about middle school. I’ve always batted, shot, bowled, etc. right handed. There’s not enough dexterity in the evidently very small part of my brain dedicated to fluent body motion to do anything complicated opposite-handed. Although I do computer-mouse left-handed. But that was a matter of starting out mousing that way when mice were invented so I could keep my dominant hand doing the important and dexterous part of the job, which was bashing in digits on a 10-key pad. Other than that exception I’m righty through and through. > [@Mean\_Mr.Mustard](#): > > This looks like a good spot for my favorite newspaper headline: That, Sir, is a thing of beauty. You made my day. ---
**Author:** ![Spice\_Weasel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spice_weasel/32/5435_2.png) [@Spice\_Weasel](https://boards.straightdope.com/u/Spice_Weasel)\ **Post date:** [November 25, 2023, 10:20pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649/45 "2023-11-25T22:20:24Z")
> [@Saint\_Cad](#): > > Can you point in the general direction of the closest large city? Mmm. No. Maybe if you gave me about five minutes to work it out. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [November 26, 2023, 9:03pm UTC](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649/46 "2023-11-26T21:03:08Z")
> [@Mean\_Mr.Mustard](#): > > This looks like a good spot for my favorite newspaper headline: Yes, the news seems to have made a splash at the time… [Previous page](https://boards.straightdope.com/t/definition-sinister-on-the-left/993649.md?page=2)