There is an acronym that us bridge teachers use called BOSTON. This stands for "Bottom Of Something" - "Top Of Nothing".
There are many times when we do not have two or three-card sequences, or an interior sequence when making an opening lead, thus we use BOSTON from broken holdings, such as 10862 or 9762 or 87532. In these situations we do NOT lead the standard card 4th from your longest suit. We lead the second highest card to show no honor. TOP of NOTHING.
Conversely, we lead low from an honor to show interest. K872 or QJ64 or A842, BOTTOM of SOMETHING. Let us look at many situations to help our partner with defense!