'Turkish-related' is a modern English compound formed from 'Turkish' + 'related'. 'Turkish' itself is the adjective form of 'Turk' with the English suffix '-ish', and 'related' comes from the past participle of the verb 'relate'.

'Turkish' developed from 'Turk' + '-ish' in Middle English; 'Turk' entered English from Medieval Latin 'Turcus' (from Byzantine Greek 'Tourkos'), ultimately from a Turkic ethnonym. 'Related' comes from Latin 'relatus', the past participle of 'referre' via Old French and Middle English.

Initially elements referred specifically to the Turk people and the Latin sense of 'brought back/connected'; over time the compound came to be used straightforwardly in English to mean 'connected with or concerning Turkey or the Turkish language/culture.'