Definition of 'Real Time'
When a system relays information to a user at a speed that is near instantaneous or has a short delay from when the event actually occurred. Online brokerages often provide a real-time data feed that displays stock quotes and their respective real-time changes, with a very insignificant lag time, so that clients can base their investing decisions on the most up-to-date information.
Investopedia explains 'Real Time'
While many financial websites do offer free stock quotes to the general public, many of these feeds are not real time and may be delayed up to 20 minutes. Therefore, when viewing stock quotes from any financial website, be aware of the time that is posted near the stock quote to verify whether the quote is actually in real time.
Possessing accurate real-time quotes is especially important for traders, as even the smallest time discrepancy between a provided quote and the real-time situation can change a profitable position into a loss.