NOTE: This definition was changed in RP-16-17 Addendum 4. Deletions have a strike-through. New text is bold.
In signal lighting: Flashes of millisecond or microsecond duration; this is a relatively new experience in signal technology, and significant claims are made for flash conspicuity. No generally acceptable vocabulary of terms has yet developed; as a result, communication between different workers is sometimes hampered by an inadequate or misunderstood vocabulary.« Back to Definitions Index