The story
Blend of Nuzleaf + Locke. From the title of Nuzlocke Comics, which features a Pokémon, Nuzleaf, drawn to resemble John Locke from Lost as a recurring character.
Etymology from Wiktionary, CC BY-SA 4.0.
nuzlocke
Today it means: A self-imposed challenge where the player can only catch the first wild Pokémon encountered in each area, and any caught Pokémon that faints cannot be used again. Full definition →