When only a small portion of the moon is visible, it is known as _______ moon.

Explanation

To answer the question "When only a small portion of the moon is visible, it is known as _______ moon," we can follow these steps:

1. **Understand the Phases of the Moon**: The moon goes through different phases based on its position relative to the Earth and the Sun. These phases include new moon, crescent, gibbous, and full moon.

2. **Identify the Relevant Phases**: The question specifically asks about a phase where only a small portion of the moon is visible. The phases of the moon can be categorized as:
- New Moon: No moon is visible.
- Waxing Crescent: A small portion of the moon is visible.
- First Quarter: Half of the moon is visible.
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