Amazon EC2 (stands for Amazon Elastic Compute Cloud) is at the core of Amazon.com's cloud-computing platform, Amazon Web Services (AWS). It allows users to distantly rent virtual computers on which they run their own applications. The service is paid by second hence the term "elastic".
"Amazon EC2" is also a name or a GIMPS user and an eponymous team, which has reported around 27000 first-time Lucas-Lehmer tests  (mostly in exponent range from 48 to 70 million, from 2011 to 2014). As of 2018, this is second biggest non-anonymous LL-test contributor in history of GIMPS.