Secular

What Does Secular Mean?
An adjective used to describe a long-term time frame, usually at least 10 years.

Investopedia explains Secular
For example, in his book "Stocks For the Long Run", Jeremy Siegel (finance professor at the Wharton School, University of Pennsylvania) argues that equity securities (particular U.S. equities) will likely outperform the other major asset classes on a secular basis, or over the long term. He backs his argument up with the fact that between 1871-2001, during any rolling 30-year period (a period long enough to be considered secular), stocks outperformed all other asset classes, in particular bonds and T-bills.