Trade winds are usually defined as those wind that blows from the eastern side to the western side. These are the prevailing winds that occur between 25° N and 25° S of the equator.
In the northern hemisphere, this wind is originated from the high-pressure tropical region (northeastern direction) and moves towards the equatorial region (low-pressure zone), and in the southern hemisphere, this wind is originated from the high-pressure tropical region (southeastern direction) and moves towards the equatorial region.
This wind is commonly known as the easterlies, named after their wind originating direction.
<span>An eon is a geologically around tens of millions of years. A period is a million year included in an eon which is also made up of several eras. Therefore my answer is a period due to it being a subset of an era which is a subset of an eon.</span>
