portent, 10**12, trillion, sign, omen, symptoms
兆 centers on a visible indication of something larger: a sign, omen, or symptom that points to a future event or underlying condition. The trillion sense is a separate numerical application, not a conceptual extension of the sign meaning.
兆 is an ancient pictograph of cracks on a heated turtle shell used in divination, representing an omen or sign. The modern form is stylized but retains the basic crack-like shape.
The four strokes look like cracks spreading out on a shell, revealing a sign or omen of what is to come.
For チョウ, imagine a fortune-teller named Chou reading the cracks: Chou -> チョウ, and the cracks show a portent.
10^12; 1,000,000,000,000; trillion
sign; indication; omen; symptom
sign; indication; omen; symptom
omen; portent; sign; presage; harbinger; premonition; precursor; foreboding; presentiment
omen; sign; notice; indication
lucky omen; good omen
1,000,000,000,000; one trillion
the people; multitude; masses
to show signs; to have symptoms; to give indications (of)
the whole nation; all the people
omen of disaster
evil omen
precursor; premonitory phenomena; telltale signs; advance warnings
divination signs
earthquake precursor
sign of happiness; good omen
Star of Death (nickname for Alcor)
auspicious sign; good omen
signs of decline