Terminology

arrow-array

A arrow array, as defined by the Apache Arrow specification, and as implemented by e.g. arro3.

sparse-array

A sparse array is mostly empty or filled with a background value (e.g. 0), with only a few values that are different. To reduce the memory footprint, sparse array objects usually only store the background value once and instead record the location of each foreground value, in various different formats.

See also pydata sparse and Sparse Arrays (scipy.sparse)

chunked-sparse-array

A sparse-array that was wrapped by a chunked array implementation (e.g., a dask array).