兆|ちょうchou[1]atamadaka (head-high)

1. numeral10^12; 1,000,000,000,000; trillion
2. nounsign; omen; indication; portent

• Synonym前兆ぜんちょうNeutralA common word for a sign that appears before something happens, as in 「噴火の前兆」. 「兆」 on its own mostly means the number trillion.
• Synonym兆候ちょうこうWrittenWritten word for signs that some change is under way, as in 「景気回復の兆候」「病気の兆候」; wide-ranging use. 「兆」 alone mostly means the number trillion.
• Related兆しきざしNeutralNative word for early signs of something beginning, as in 「回復の兆し」. 「兆」 alone usually means the number trillion; its omen sense mostly survives in compounds.
• Related気配けはいNeutralA sign or presence you sense intuitively, as in 「春の気配」「人の気配」; the emphasis is on feeling it. 「兆」 alone leans toward the numeric sense.
• Related徴しるしWrittenWritten word for a sign that foretells something; also written 「験」. Seldom used alone — everyday speech prefers 「兆し」, while 「兆」 alone mostly means the number.
• Related予兆よちょうWrittenA written-flavored word for a sign before something happens, as in 「地震の予兆」. 「兆」 is rarely used alone in the omen sense.
• RelatedオーメンNeutralLoanword for an ill omen; for many it evokes the horror film of that name. Rare in daily use — say 「前兆」 or 「兆し」 instead.

Use 「兆」 for the number trillion, as in 「一兆円」; its omen sense mostly appears in compounds like 「吉兆」「前兆」. For signs of something emerging pick 「兆し」 or 「兆候」; for an advance warning 「予兆」; for a presence you sense, 「気配」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 「億おく」の次つぎ、「京きょう」の前まえの単位たんい、一兆いちちょうは1億いちおくの一万いちまん倍ばい。