presage
Meaning: an omen
Usage: The dark clouds were a presage of the storm approaching.
portent
Meaning: an omen
Usage: When a black cat crossed my sister’s path while she was walking to school, she took it as a portent that she would do badly on her spelling test.
semaphore
Meaning: a visual signal
Usage: Anne and Diana communicated with a semaphore involving candles and window shades.
figurative
Meaning: symbolic
Usage: Using figurative language, Jane likened the storm to an angry bull.