1. a person with Down Syndrome
2. any mentally retarded person

A reference to the fact that people with Down Syndrome have three copies of the 21st chromosome (hence the other name of the syndrome, trisomy 21), while normal people only have two. Therefore, while most people ride "bicycles" down "21st street", people with Down Syndrome ride "tricycles." They are trike riders.

A catch all word to describe anything that is basic, uncool or untrendy. According to The New York Times, "cheugy (pronounced chew-gee) can be used, broadly, to describe someone who is out of date or trying too hard."

Things that are cheugy:

The New York Times
PT Cruisers
Goldendoodles

Australians

Addison Rae
White people
Billionaires

The person writing this definition