Glossary
District court
In the federal system, the trial court: every state has at least one U.S. District Court. Some state systems also use "district court" for their trial courts (with the meaning depending on the state).
There are 94 federal district courts across the U.S. and territories. Bigger states are split into multiple districts: California has four (Northern, Eastern, Central, Southern), Texas has four, New York has four. Smaller states often have just one.
A federal lawsuit is filed in a specific district court, and that court hears the trial, sets the schedule, and issues the original judgment. Appeals from a district court go to the U.S. Court of Appeals for the Circuit that includes that district.
In Texas, "district court" is also the name for the state's main trial court: completely separate from the federal courts. Context matters.