noun
a system of signaling, especially a system by which a special flag is held in each hand and various positions of the arms indicate specific letters, numbers, etc.
EXAMPLES OF SEMAPHORE
adjective
fine; completely satisfactory; OK.
EXAMPLES OF COPACETIC
noun
an environmental cue, as the length of daylight or the degree of temperature, that helps to regulate the cycles of an organism's biological clock.
EXAMPLES OF ZEITGEBER