Artuz v. Bennett
In Artuz v. Bennett, 531 U.S. 4, 8-9, 121 S.Ct. 361, 148 L.Ed.2d 213 (2000), the Supreme Court construed the meaning of "properly filed" as follows:
An application is "properly filed" when its delivery and acceptance are in compliance with the applicable laws and rules governing filings. These usually prescribe, for example, the form of the document, the time limits upon its delivery, the court and office in which it must be lodged, and the requisite filing fee. ... But in common usage, the question whether an application has been "properly filed" is quite separate from the question whether the claims contained in the application are meritorious and free of procedural bar.