sign; indication; omen; symptom
Refers to an early, often faint, sign that something is beginning or about to happen. Can be positive or negative, and is used for both concrete phenomena (e.g., symptoms) and abstract developments (e.g., economic recovery).
景気回復の兆しが見え始めた。
Signs of economic recovery have begun to appear.
There were signs of fatigue on his face.
Signs of economic recovery are starting to appear.
The illness is showing signs of improvement.
There are signs that a typhoon is approaching.
兆し is a broad, common word for any early sign or omen, while 萌芽 specifically frames that sign as the germinating start of something that will grow further.