Centre-weighted Average Metering
A metering pattern that averages the whole frame while giving most of the weight — typically 60 to 80 per cent — to the central area.
In depth
It predates evaluative metering and survives because it is completely predictable: the same scene always meters the same way, so a photographer can learn its bias and compensate reliably. It also ignores the focus point, which matters when composing with a fixed centre point and recomposing.
Examples in practice
Portrait photographers who always place the head near centre often prefer it to matrix metering for its consistency across a sequence.