The term DROP FROM NIOBE is a reference to Greek mythology. In the story, Niobe was a proud mother who boasted about her children and insulted the goddess Leto. As punishment, Leto sent Apollo and Artemis to kill all of Niobe's children. This resulted in Niobe weeping uncontrollably and her tears caused her to be turned into stone. The answer to the crossword clue TEAR (4 letters) is DROP, which refers to the tears that Niobe shed when her children were killed.