mid-15c., "a summary or abstract," of unknown origin, perhaps a diminutive form related to dock (v.). An early form was doggette. Meaning "list of lawsuits to be tried" is from 1709.
Entries linking to docket
dock n.1
"ship's berth, any structure in or upon which a ship may be held for loading, repairing, etc.," late 15c., dokke, from Middle Dutch or Middle Low German docke, which is perhaps ultimately (via Late Latin *ductia "aqueduct") from Latin ducere "to lead" (from PIE root *deuk- "to lead"); or possibly from a Scandinavian word for "low ground" (compare Norwegian dokk "hollow, low ground"). The original sense was perhaps "furrow a grounded vessel makes in a mud bank."