出典:Wiktionary
From Classical Persian تاجیک (tājīk, “non-Turk (of Central Asia)”) (akin to تازی (tāzī), تازیک (tāzīk)), (ultimately) from Middle Persian tʾcyk' (tāzīg, “Arab”), (ultimately) from Arabic طَيِّئ (ṭayyiʔ, “name of an Arab clan”). See Tayy
Popular folk etymology traces the word to Tajik тоҷ (toj, “crown”) (see Arabic تَاج (tāj), from Persian تاج (tâj, “crown”)), but this is false.
Tajik (複数形 Tajiks)
Tajik (not comparable)
Refers to ethnicity, not nationality. Compare Tajikistani (“inhabitant of nation of Tajikistan; pertaining to Tajikistan”).