it refers to the act of the president of staying the execution of a convict
Stay of execution In cases where the death penalty has been imposed, a stay of execution is often sought to defer the execution of the convicted person. This may occur if new evidence is discovered that will exonerate the convicted person or in attempts to have the sentence commuted to life imprisonment. In the United States, all death sentences are automatically stayed pending a direct review by an appeals court. If the death sentence is found to have been legally sound, the stay is lifted.
List of people granted executive clemency by Barack Obama By the end of his presidency on January 20, 2017, Barack Obama had exercised his constitutional power to grant executive clemency—that is, "pardon, commutation of sentence, remission of fine or restitution, and reprieve"[1]—to 1,927 individuals convicted of federal crimes. Of the acts of clemency, 1,715 were commutations (including 504 life sentences) and 212 were pardons.[2] Most individuals granted executive clemency by Obama had been convicted on drug charges,[3] and had received lengthy and sometimes mandatory sentences at the height of the War on Drugs.[4]