Live Entropy Source definition in Computer Security terms:
Definition(s): An approved entropy source (see NIST SP 800-90B) that can provide an RBG with bits having a specified amount of entropy immediately upon request or within an acceptable amount of time, as determined by the user or application relying upon that RBG.
Source(s): NIST SP 800-90A Rev. 1
reference: CSRC Glossary