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):
A home built in the mid 1900s can be renovated to have the similar amenities as one constructed within the past few years. This is where effective age comes in. Chronological age is the time from when a house was built to the present day. On the other hand, the effective age refers to how old the home appears to be. This term encompasses the condition, efficiency and the functional utility of a property. Effective age can be higher or lower than chronological age.