It means that a judgment (in whatever type of case it was) has been entered by the court. Without further information there's no way to answer more.
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The date "judgment entered" date has a practical application in many cases in Massachusetts. First of all, it is an administrative act taken by the clerk's office of the court you are in. Practically speaking, the date "judgments enters" is usually the day the calculation of your appeal period begins. Although not entirely on point with your question, here is an example. In the eviction context, most eviction trials occur on Thurdays. If the Landlord goes to trial and wins his case on Thursday, judgment for the Landlord does not "enter" until the next day, Friday. It is from that Friday that the tenant's 10 day appeal period begins to run. (Sometimes, duly to a delay in he Clerk's office, the judgment may not enter for several days, in which case, the appeal period is prolonged.) On the other hand, if the parties enter into an Agreement for Judgment (rather than going to trial), whatever day the Agreement is filed with the Court will be the "Judgment Entered" date. My point is that "judgment entered" probably wont' be the same day you lost at trial; the judgment entered date may be different in the context of your case, but pay attention to the specific date, because it will be of practical importance.
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