collier:
(also ‘coal miner‘ or ‘coalminer’; plural: ‘colliers‘; pronunciation: the letter ‘c’ is said with a ‘k’ sound as in “king” — for the right pronunciation of this word, please click here)
a person who works in a coal mine digging out coal; a miner;
(very old usage) a person who sells coal,

a collier/coal miner
A collier is a coal miner who digs out coal at a coal mine.
The life of a collier in the past was very miserable with very little sanitation and health facilities.
In and around collieries, children as young as six years old began their life as colliers, and died early from black lung or killed in mine accidents which were very common in those days.

a collier (coal ship) unloading coal
Note: ‘Collier’, always with a capital ‘c’, is often found in the names of people, e.g. Paul Collier, William Collier, Cathy Collier, etc., and is also found in the names of places, e.g. Collier County, Collier Place, Collier Yard, etc.
