I have a quibble here. A hash table, the basic CS data structure, is not a two-dimensional data structure like a map, it is a one-dimensional data structure like a list. You can use a hash table to implement a Map/Dictionary, and essentially everyone does that. Sets are also often implemented using a hash table.
The basic operations of a hash table are adding a new item to the hash table, and checking if an item is present (potentially removing it as well). A hash table doesn't naturally have a `V get(key K)` function, it only naturally has a `bool isPresent(K item)` function.
This is all relevant because not all maps use hash tables (e.g. Java has TreeMap as well, which uses a red-black tree to store the keys). And there are uses of hash tables besides maps, such as a HashSet.
Edit: the term "table" in the name refers to the internal two-dimensional structure: it stores a hash, and for each hash, a (list of) key(s) corresponding to that hash. Storing a value alongside the key is a third "dimension".
The basic operations of a hash table are adding a new item to the hash table, and checking if an item is present (potentially removing it as well). A hash table doesn't naturally have a `V get(key K)` function, it only naturally has a `bool isPresent(K item)` function.
This is all relevant because not all maps use hash tables (e.g. Java has TreeMap as well, which uses a red-black tree to store the keys). And there are uses of hash tables besides maps, such as a HashSet.
Edit: the term "table" in the name refers to the internal two-dimensional structure: it stores a hash, and for each hash, a (list of) key(s) corresponding to that hash. Storing a value alongside the key is a third "dimension".