[1675–85; denticulate + -ion]This word is first recorded in the period 1675–85. Other words that entered Englishat around the same time include: constitutional, denature, eclectic, mouthpiece, muscular-ion is a suffix, appearing in words of Latin origin, denoting action or condition, usedin Latin and in English to form nouns from stems of Latin adjectives (communion; union), verbs (legion; opinion), and esp. past participles (allusion; creation; fusion; notion; torsion)