Deus Ex Macchiato, What is a run on a CCP, here. Gorton and Metrick reference and link is useful.
A run on a bank occurs when depositors withdraw deposits quickly. In the days before deposit insurance, bank runs from retail depositors were common as their money was genuinely at risk from bank failure. These runs were damaging as banks which were solvent but not sufficiently liquid (due to demand deposits funding term loans) could fail due to a run. These days, bank runs occur in the wholesale funding market: hence Gorton and Metrick’s influential paper about the run on repo in the 2008 crisis. These repo runs occur if wholesale funders refuse to carry on providing liquidity.