What do you understand by shriller sound?

Explanation

**Step-by-Step Solution:**

1. **Definition of Shriller Sound**: A shriller sound is characterized by a high pitch. This means that when we describe a sound as shrill, we are referring to its high frequency.

2. **Understanding Pitch**: Pitch is the quality of a sound that allows us to classify it as high or low. Higher pitch sounds are perceived as shrill, while lower pitch sounds are perceived as deep or bassy.

3. **Relationship Between Frequency and Pitch**: The pitch of a sound is directly related to its frequency. Frequency is the number of vibrations or cycles per second of a sound wave, measured in Hertz (Hz).

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