A quiver, tremor, or fluctuation — a noun describing a slight shaking or wavering (emotionally, physically, or in tone).
彼女の声に揺らぎがあって、心配になった。
There was a quiver in her voice, and I became worried.
ろうそくの炎の揺らぎが部屋に影を作る。
The flicker of the candle flame casts shadows in the room.
決断の揺らぎがチームの士気に影響した。
Wavering in the decision affected the team's morale.
Statistical fluctuation — the variability or fluctuation in data or measurements (used in statistics, physics, etc.).
測定値の揺らぎを考慮して、平均値を算出した。
Taking into account the measurement fluctuations, we calculated the average.
この実験では揺らぎを小さくするために条件を統一した。
In this experiment, we standardized the conditions to reduce fluctuations.