When a track is muted using its Mute button, the regions on the track are gray, but the region names are in color.
When a track is turned off using its On/Off button, both the regions on the track and the region names are gray.
When an individual region is muted, the region and its name are gray, and a small colored dot precedes the name.
When a track is muted because another track is soloed, the regions on the track are gray, but the region names are in color.
Download the guides:
Logic Pro User Guide: PDF