Calque of English 'hash': 散 'scatter' + 列 'array/list' = 'scattered list.' Mainland tech writing more often uses the transliteration 哈希 (hāxī); 散列 is more common in Taiwan and in formal CS textbooks.
memory
Picture taking an ordered list and 'scattering' (散) the entries across an array (列) according to a key — that's exactly what a hash table does.
