From The Collaborative International Dictionary of English v.0.48:
Dime \Dime\ (d[imac]m), n. [F. d[^i]me tithe, OF. disme, fr. L.
decimus the tenth, fr. decem ten. See Decimal.]
A silver coin of the United States, of the value of ten
cents; the tenth of a dollar.
[1913 Webster]
Dime novel, a novel, commonly sensational and trashy, which
is sold for a dime, or ten cents; -- they were popular
from ca. 1850 to ca. 1920. Sometimes the term is still
applied to any novel of the type, though the price has
greatly increased.
[1913 Webster +PJC]