1
general::
The beginning or end of a particular century, as in That idiom dates from the turn of the century, that is to say, about 1900. This expression was first recorded in 1926.
American Heritage Idioms
2
general::
Phrase(s): the turn of the century
the time when the year changes to one with two final zeros, such as from 1899 to 1900. (Although technically incorrect—a new century begins with the year ending in 01—most people ignore this.) • My family moved to America at the turn of the century. • My uncle was born before the turn of the last century.
McGrawhill's American Idioms And Phrasal Verbs