Strictly speaking, a hash table is a data structure that stores one or more key and value pairs and uses the hashFunction of the key to compute an index into an array of buckets or slots, from which the correct value can be retrieved. Ideally, the hashFunction should assign each key to a unique bucket, provided that you have the required number of buckets.
A good hashFunction must be able to produce a uniform distribution of hash values because it is inefficient to have unused buckets or big differences in the cardinalities of the buckets. Additionally, the hashFunction should work consistently and output the same hash value for identical keys because otherwise it would be impossible to find the information you ...
