1) a sign, mark, token

a) that by which a person or a thing is distinguished from others and is known

b) a sign, prodigy, portent, i.e. an unusual occurrence, transcending the common course of nature

1) of signs portending remarkable events soon to happen

2) of miracles and wonders by which God authenticates the men sent by him, or by which men prove that the cause they are pleading is God's

[View this word in Trench's Synonyms here.]