The act of retaining; the power of retaining, specially ideas in the mind; restraint.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (noun) (n.) (noun)
The act of keeping, or state of being kept, in possession; act or power of keeping things in the mind; memory.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (noun) (n.) (noun)
The act or power of retaining, as in the memory; the undue withholding of some natural discharge; restraint.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (noun) (n.) (noun)
Act or power of retaining: memory: restraint: custody.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (noun) (n.) (noun)
Act of retaining.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (noun) (n.) (noun)

Usage examples:

For I had been reflecting upon the capacity of human mind for retaining secrets and had come to the conclusion that it is so constructed that its power of retention is remarkably small.
- The Blue Germ by Martin Swayne
This is commonly called " cornering" an edition; and when several persons possessing the same opinions and the same tastes join their forces, it will readily be perceived that if a book will not go up of its own accord it may readily be forced up by judicious retention and self- denial.
- Book Collecting A Guide for Amateurs by John Herbert Slater
Taking no share in education within its own walls- having, that is to say, none of the usual routine of college lectures and so on- it has had to justify the retention of its wealth.
- Oxford by Frederick Douglas How