‘Chiliad’ first appeared in the late 1500’s, but it has slowly been replaced by the word millennium.
Someone who may be quite outgoing or generally loud could be described as ‘Rambunctious’.
If someone is calm and untroubled they are also ‘insouciant’.
‘Biodegradable’ products are environmentally friendly, as well as avoid pollution.
For example, if two businesses ‘amalgamate’ they will come together to form one larger organisation.