highlight-symbol-at-point is an alias for `hi-lock-face-symbol-at-point' in `hi-lock.el'.

It is bound to M-s h ..


Highlight each instance of the symbol at point.
Uses the next face from `hi-lock-face-defaults' without prompting,
unless you use a prefix argument.
Uses `find-tag-default-as-symbol-regexp' to retrieve the symbol at point.

This uses Font lock mode if it is enabled; otherwise it uses overlays,
in which case the highlighting will not update as you type.