The interjection is always a spoken word that
expresses an emotion, The word 'interjection' arises from
the Latin 'inter' meaning 'between' and 'iacere', to
cast. Other English words such as adjective, eject,
inject and jet are derived from the same root of
'iacere'.
Interjections are often followed by an exclamation
mark.
Oh! Gosh! Wow! Ouch! Hey!