hyponym
Linguistics term for a word whose meaning is included within a broader term (上位語). For example, 犬 is a hyponym of 動物.
See also: 上位語
narrower term
Computing/information science term for a more specific concept in a taxonomy or thesaurus.
"Dog" is a hyponym of "animal."
In a thesaurus, you can navigate from narrower terms to broader terms.
Compound of 下位 (lower rank) + 語 (word).