Calm; quiet period (4)
I believe the answer is:
lull
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">calm</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that calm can be written as lull)</span><br/ ><br/ >'<span class="explanation-format__original">quiet period</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for lull that I've seen before include "Put to sleep - respite" , "Pause in activity" , "Rock to sleep" , "Calm; allay (fears)" , "Soothe; quiet interval" .)