Looking at the [_Corpus of Contemporary American English_][2], I get the [following data][1] (the chart shows the result of the search, which include phrases using both the singular and the plural): ![enter image description here][1] Looking at the sentences included in the CoCA, it doesn't seem _prerequisite_ is used with different meanings. > Does one seem like a **prerequisite for** the others? <!-- break --> > Since primacy in undersea warfare is a **prerequisite for** other naval operations, priority must be given to expanding the navy's edge […]. <!-- break --> > According to Humboldt (Aksan, 1998), language is **a prerequisite to** the materialization of thought. <!-- break --> > The **prerequisites of** these procedures are the reader's actual and fictional encyclopedias -- they are individually differentiated. <!-- break --> > Thus, for Central Asia, two indispensable **prerequisites of** a future democratic evolution are the avoidance of either internal or interstate wars and the continuing external pressure for reform to reinforce the efforts of domestic reformers and to achieve a more broadly based, transparent, and legitimate basis for domestic security. <!-- break --> > A **prerequisite to** fostering a full understanding of mentor programs is developing a definition that applies equally to the community college setting and business or pre-college programs. <!-- break --> > The first **prerequisite to** thinking creatively is the desire to think imaginatively and a good place to start that process is by noticing creative images in magazines, cartoons, TV and movies. [1]: https://i.sstatic.net/215y0.png [2]: www.americancorpus.org