According to Mayo Clinic, Down syndrome causes a distinct facial appearance, intellectual disability, developmental delays, and may be associated with thyroid or heart disease in a person. So calling people with this syndrome 'Mongoloid' is extremely vulgar and disrespectful to ethnic Mongolians. Likewise, how will the population react if Down Syndrome was associated with 'European' looks? If you use this term, you are automatically a xenophobic, in my opinion.
If any difference is noteworthy, it would probably be that an age is usually between two times, e.g. 1290-1450AD, whereas an era is less set - but that isn't a rule, its just a matter of usage. Synonyms would be epoch, or eon. Source(s):
â¢ ERA (noun) The noun ERA has 3 senses: 1. a period marked by distinctive character or reckoned from a fixed point or event. 2. a major division of geological time; an era is usually divided into two or more periods. 3. (baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched. Familiarity information: ERA used as a noun is uncommon.