A partial solar eclipse occurs when the Moon comes between the Sun and the Earth, but the moon does not fully cover the sun's disk, only partially.
When it is a partial solar eclipse, the Sun, the Moon and the Earth do not align perfectly in a straight line, and hence, only the outer part of the Moon's shadow, which is called the 'penumbra', is visible on the Earth's surface. If one thinks about it, when a during a partial solar eclipse, it looks like the Moon has taken a bite out of the Sun.
Also See: Partial Solar Eclipse on 6th January 2019: When, Where, How to watch Surya Grahan in India and details to keep in mind
Sometimes, during a partial or annular solar eclipse , the Moon covers only a tiny part of the Sun's disk. Many times a partial eclipse also looks like a total eclipse. Generally, we refer to the size of the eclipsed area is as the eclipse magnitude.
In a year, we witness for about 2-5 solar eclipses and they are usually named for their darkest, or maximum point. Here are some spectacular photos from last year's annular or partial solar eclipses that took our breath away!
Also See: Partial Solar Eclipse 2019: Precautions for pregnant women