The word "diminished" has two possible meanings, depending on its context.
1) If used in a musical sense, it refers to a chord that is built by starting with a major or minor chord and then removing one or more notes from the chord until it becomes a diminished chord (also known as an "augmented" chord). This type of chord can create a dissonant or unresolved sound, which is often used for dramatic effect in music.
2) If used outside of the musical context, "diminished" may refer to something that has been reduced in size, importance, value, or quality. For example, if someone says they feel diminished after a breakup, it means they feel smaller, less important, or worthless as a result of the relationship ending.