Every term is defined twice: once the way a filing would put it, and once the way somebody would explain it to you across a table. The second one is usually the one that sticks.
Showing 3 terms
A nine-period EMA of the MACD line, used as the trigger for MACD crossovers.
The classic MACD signal, and a late one. It whipsaws badly in ranging markets, which is precisely why the zero-line filter exists.
The bars in a MACD display, plotting the gap between the MACD line and its signal line.
The component that turns first, and the noisiest of the three. Shrinking bars while price still rises mean the driver has lifted off the accelerator.
Moving Average Convergence Divergence — the gap between a fast and a slow EMA, plus a signal line and histogram.
Two averages arguing. The histogram turns first and is the most useful part.