Definition of Dramatic Irony
The climax of Trifles features an instance of dramatic irony. Throughout the play, the men continuously belittle the women's concern with "feminine" details, such as the flaws in Minnie's knitting. However, this attention to the remnants of Minnie's activity—particularly those coded as female—ultimately lead the women to uncover the motivation behind the murder. In this case, the dramatic irony at play is produced by the fact that the audience knows something that the men don’t know—namely, that the women have found the key piece of evidence that could be used to convict Minnie and, moreover, that the men have ignored this evidence and written it off as "women's trifles."
The County Attorney says facetiously to Mr. Hale:
“Well, Henry, at least we found out that she was not going to quilt it. She was going to—what is it you call it, ladies?”