What is "mindstream"

n. (''Buddhist philosophy'') The succession of moments of consciousness proceeding endlessly from lifetime to lifetime.

Mindstream (citta-santāna) in Buddhist philosophy is the moment-to-moment continuum (Sanskrit: saṃtāna) of sense impressions and mental phenomena, which is also described as continuing from one life to another.The Noble Eightfold Path: The Way to the End of Suffering by Bhikkhu Bodhi

http://www.buddhanet.net/pdf_file/noble8path6.pdf