The word "事儿" is formed through a phonetic and informal fusion of the base character 事 (shì), meaning "matter" or "affair", with the colloquial suffix 儿 (ér). In northern Mandarin, particularly in the Beijing dialect, this suffix is often merged with the preceding syllable not as a separate sound but by slightly curling the tongue at the end of the pronunciation, creating a single, softened syllable (shìr). This process, called "érhuà" or rhotacization, transforms the more formal "事" into a casual, spoken form that often implies a sense of familiarity, triviality, or liveliness.