Comp sci vs the natural sciences have an interesting split on this (though blurring more recently). Computer science tends to use "code" as a collective noun. T

Comp sci vs the natural sciences have an interesting split on this (though blurring more recently). Computer science tends to use "code" as a collective noun. Traditional usage in the natural sciences and parts of engineering is that "a code" (singular) is a single routine or piece of software to carry out some kind of numerical calculation or simulation. Then "codes" is just the normal plural when talking about more than one of them. So you find papers talking about things like "a new code for simulating preheating" [1] or "benchmarking simulation codes" [2]. [1] https://doi.org/10.1088/1475-7516/2008/11/009 https://doi.org/10.1088/1475-7516/2008/11/009 [2] https://doi.org/10.1109/PAC.2003.1289206 https://doi.org/10.1109/PAC.2003.1289206