'psittacid-related' originates from English, combining 'psittacid' and 'related'. 'psittacid' ultimately comes from New Latin 'Psittacidae', which derives from Latin 'psittacus' and Ancient Greek 'psittakos' meaning 'parrot'; 'related' derives from Latin 'relatus' (past participle of 'referre') via Old French and Middle English.

'psittacid' developed from New Latin 'Psittacidae' (the family name for true parrots), itself from Latin 'psittacus' and Greek 'psittakos'; the English adjective 'psittacid' was formed from these scientific/Latin roots. 'related' evolved from Latin 'referre' → past participle 'relatus' → Old French and Middle English forms before becoming the modern English adjective 'related'.

Initially the root 'psittacid' referred specifically to the parrot family in scientific Latin; over time its use in English has been extended to form compounds (e.g., 'psittacid-related') meaning broadly 'connected with or characteristic of parrots'. The component 'related' has retained the sense of 'having a connection to'.