Remaster: Its a updated version improved graphics and audio while largely keeping the original core experience intact (The Zombies chronicles maps in BO3)
Remake: Its a brand new version that its build from the ground with modern graphics and updated gameplay mechanics but still keeps the overall foundation of the map (Alpha omega is a remake of Nuketown zombies)
Reimagining: Its making a new take on a preexisting concept, creating new stuff and making significant changes to the story, characters and gameplay while taking inspiration from the original source material (Ashes of the Damned is a reimagining version of Tranzit because it takes the same concept of making a huge map with different POI's and having to use a transportations system to navigate throughout the map)
I wanted to make this post so people can know the difference between remaster, remake and reimagining