The phrase "a single credit" is correct and usable in written English.
You can use it when referring to one unit of credit, often in the context of education or finance.
Example: "To complete the course, you need to earn a single credit in this subject."
Alternatives: "one credit" or "a lone credit".
I have a single credit card.
They must have a balance sheet big enough to accommodate so large a single credit without worrying regulators.
His credits began to taper off after 1933, and in 1936 Mankiewicz didn't get a single credit.
The service, however, monitors information from a single credit bureau, Experian, one of the three big credit-reporting agencies (along with Equifax and Trans Union.
The similarly troubled Gone With the Wind had at least eight writers, including Sidney Howard, the Pulitzer Prize-winning playwright who took a single credit, and five directors.
In recent days, the cost of a single credit card has been between 40 cents and $5 depending on the level of authenticating information provided.
Drivers across Europe will soon be able to use a single credit-card-sized, counterfeit-proof driver's license that will do away with the 110 different versions that exist in the 25-nation bloc.
If we consider college, or at least the fraction of college that corresponds to a single credit-bearing course, then we can do some experimental math which will confront us with questions regarding what we're actually paying for when we pay for education.
On 30 June, a single credited to the Sex Pistols was released: on one side, notorious criminal Ronnie Biggs sang "No One Is Innocent" accompanied by Jones and Cook; on the other, Vicious sang the classic "My Way", over both a Jones Cook backing track and a string orchestra.
A single-credit clearance of 'Yie Ar Kung-Fu'.
Iain Duncan Smith, the work and pensions secretary, will replace all working age benefits and tax credits with a single universal credit.
