A credit was a generic term for a monetary unit. Many worlds and civilisations described their money with the term. While they were not the same system, they often (but not always) referred to a currency system that operated electronically, rather than using currency (i.e., notes and coins).
Examples of monetary systems Edit
Human usage Edit
In the year 2050 credits (sometimes called "creds") were the currency in Department-controlled Britain. (TV: The Custodians, Oroborus) By 2062 the UK no longer used credits and had switched to the Euro. (PROSE: The Last Dodo)
In the year 200,000, a Kronkburger on-board Satellite Five cost 2 credits 20. A head chip cost 100 credits and a full Infospike cost 10,000 credits. (TV: The Long Game) A hundred years later, Rodrick won a reward of 1600 credits "courtesy of the Bad Wolf Corporation" on The Weakest Link, only to be exterminated by the Daleks before he could receive it. (TV: Bad Wolf/The Parting of the Ways)