To display a menu option in a dimmed, fuzzy typeface to indicate that this option is no longer available.

In passive detection, one of the intersection points of lines of position which do not represent actual targets but are only crossover points of multiple plotted lines of position from two or more detection stations.

The discernible outline of the shape of a former crystal or of another rock structure that has been partly obliterated and has as its boundaries inclusions, bubbles, or other foreign matter. Also known as phantom.