Kelly betting
From the BJ Glossary:
Kelly betting. Betting a proportion of your bankroll equal to advantage divided by the variance of the possible outcomes. This style of betting is intended to minimize the risk faced by a bettor and most betting schemes recommended by serious blackjack experts are a modification of this style of betting.
jj, you will find the glossary and other blackjack reference information on this website helpful to you. Look at the left side of your screen for BJ Glossary and BJ Reference. Read through all the entries -- a lot of your questions will be answered there.