What Does By Mistake Mean?

By Mistake Meaning

Definition: To commit an error unintentionally.

If you do something by mistake, you have done something you didn’t mean to do or didn’t intend to do.

Since it was done accidentally, you usually don’t realize the mistake until after it’s been done and someone has pointed it out to you. Usually, it is something negative, but it may be neutral or even positive.


Origin of By Mistake

Sentence with mistake Mistake is a Middle English word from the 14th century that meant to commit an offense. It is unclear when it was combined with by for the first time to make a prepositional phrase, but we can see examples of it from an 1842 Democratic Standard:

  • Another development— A number of the Weekly Ohio State Journal has found its way to us by mistake, and an awkward mistake, it seems to us to have been; the envelope was indorsed ‘Madisonian,’ but on the inside it was directed to a certain paper in the State of New York.

and in this humorous definition of hard luck from the Chicago Day Book in April 1864:

  • Hard Luck— For a poet to write a poem on his cuff to raise money to pay his laundry bill and then send the cuff to the wash by mistake.

Examples of By Mistake

Define by mistake In the modern day, people often say they did something by mistake when making an excuse.

For example, someone might say,

I wrote the wrong name by mistake. The gift is meant to have your name on it; I promise.


  • I picked out the wrong juice by mistake. I’ll get the right one tomorrow.

You could also say,

  • We got to the movie early by mistake, so we took a walk around the block.

More Examples

  • An inmate who was released from Norwich Prison three weeks early by mistake has been asked to hand himself back in, it has emerged. –Norfolk Eastern Daily Press
  • Police move sick driver’s car then blow it up by mistake. –The Guardian


To do something by mistake means to do it accidentally and unintentionally.