Of course, the word trifles means something of little value or importance; however, as the title of Susan Glaspell's play, the word is certainly used ironically as it is, indeed, the seemingly meaningless things, mere "trifles" that women are "used to worrying over," as Mr. Hale remarks, that unlock the secret of Mrs. Wright's motive for killing her husband.
Clearly, then, another significance to the title of Trifles is the marked divide in the psyches of men and women, a major theme in the one-act play. For, George Henderson, the county attorney who looks around the kitchen before searching upstairs, asks the sheriff,
"You're convinced that there was nothing important here--nothing that would point to any motive?"
and the men then ignore that room because it contains, as the sheriff assumes, "Nothing here but kitchen things." And, it is with more irony that Glaspell writes of the men as the county attorney tells the sheriff he would like to see any of the things that Mrs. Peters, who was to do some alterations for Mrs. Wright, takes with her and "keep an eye out for anything that might be of use to us." So, here he does consider that a trifle may be something of use. But, the irony of this is the fact that the trifle that is of the most use goes not with Mrs. Peters, but with Mrs. Hale who hides in her pocket--yet another mere "trifle" as it is the simple difference of one woman over the other hiding the "trifling" bird--a difference that "makes all the difference."
The word trifle, then, exceeds its definition in Glaspell's play as it is the trifles and the failure to recognize their significance that prevents the men from solving the case of Mrs. Wright's murder of her husband.