A bowed string instrument is a type of musical instrument that has strings which are played by using a bow.
Imagine you have a wooden stick with some strings attached to it, and then you have this special stick called a bow that you use to make the strings vibrate and make music.
The bow has something called horsehair on it, which is like really soft and fluffy hair from a special kind of animal. You hold the bow and move it up and down on the strings, and the horsehair on the bow rubs against the strings to make them make sound.
The strings are stretched tightly between two parts of the instrument, so when you pull the bow across them, they vibrate and create sound. It's like when you pluck a rubber band and it makes that "boing" sound.
There are different sizes and kinds of bowed string instruments. Some of the most common ones are the violin, which is small and high-sounding, the viola, which is a little bigger and a bit lower-sounding, and the cello, which is really big and low-sounding.
Each instrument has different strings that make different sounds. The violin has four strings, the viola has four strings too but they are thicker and lower in pitch, and the cello has four strings that are even thicker and make very deep sounds.
The way you play these instruments is by pressing down on the strings with your fingers in different places to change the pitch, or how high or low the sound is. You can also move the bow faster or slower to change how loud or soft the sound is.
Bowed string instruments are really important in making beautiful music. They can play by themselves or they can play together with other instruments to make an orchestra. When you hear music that sounds really lovely and emotional, there's a good chance that a bowed string instrument is playing.