Mind-wandering

Experience of thoughts not remaining on a single topic for a long period of time

Mind-wandering is loosely defined as thoughts that are not produced from the current task. Mind-wandering consists of thoughts that are task-unrelated and stimulus-independent. This can be in the form of three different subtypes: positive constructive daydreaming, guilty fear of failure, and poor attentional control.

This keyword could refer to multiple things. Here are some suggestions: