'coal-associated' originates from English, specifically from the words 'coal' and 'associated', where 'coal' ultimately comes from Old English 'col' meaning 'coal' and 'associate' derives from Latin 'associare' in which elements related to 'to' and 'companion' conveyed joining or linking.

'associated' changed from Old French 'associer' and Latin 'associare' through Middle English forms (for example 'associaten') and became Modern English 'associate/associated'; combining this participial adjective with 'coal' produced the compound adjective 'coal-associated' in Modern English.

Initially the components meant 'coal' and 'to join or connect'; over time their combination came to be used adjectivally to mean 'connected with or related to coal'.