(computer science) Distance from the root node of a tree structure.
(video game) One of several discrete segments of a game generally increasing in difficulty. Often numbered. Often, each level occupies different physical space (levels don't require any direct physical relationship to each other, e.g. vertically stacked, horizontally chained, etc).
(especially) Something that transcends people’s differences (such as social class, wealth, etc.); something that tends to eliminate advantages and disadvantages.
A person holding a political opinion in favor of eliminating disparities between the haves and the have nots.