The northern pike (Esox lucius) belongs to the genus Esox and is a carnivorous fish species. It primarily inhabits brackish and freshwater environments in the Northern Hemisphere, displaying a holarctic distribution. In Great Britain, Ireland, most of Eastern Europe, Canada, and the United States, it is commonly referred to as simply "pike" (plural: pike).

These pike have the capacity to attain considerable dimensions, with an average length of approximately 40-55 cm (16-22 in). The largest recorded specimens have reached up to 150 cm (59 in) in length, weighing up to 28.4 kg (63 lb), as documented. The International Game Fish Association (IGFA) currently recognizes a world-record northern pike weighing 25 kg (55 lb), caught by Lothar Louis in Greffern Lake, Germany, on 16 October 1986.

In Eurasia, northern pike generally achieve larger sizes compared to their North American counterparts, with coastal regions of Eurasia typically yielding larger individuals than inland areas.