Wide-area AF
An area mode in which the camera considers the entire frame when choosing what to focus on.
In depth
Left to itself, the algorithm traditionally chose whatever was nearest and highest in contrast, which is often a foreground branch rather than the subject. Combined with modern subject detection the mode becomes far more useful, because the camera is now identifying a face or an animal rather than simply finding an edge.
Examples in practice
With bird detection enabled, wide-area AF finds a kestrel anywhere in frame instead of locking onto the nearest fence post.