An engineering report was a report prepared by engineering personnel aboard Federation starships outlining the status of technological systems aboard the starship. They were usually submitted to the first officer detailing damage sustained to ship's systems and estimates on the time required to complete repairs, such as after a battle.
Chakotay discussed an engineering report from B'Elanna Torres with Captain Kathryn Janeway after the incident with the Borg, noting it would take two weeks to remove the Borg technology. (VOY: "Scorpion, Part II")
After a genome thief had taken over Tom Paris's appearance, Chakotay mentioned to "Tom" that Captain Janeway was interested in implementing some of Steth's technology, described in the real Tom's engineering report. (VOY: "Vis à Vis")