A parsec is a unit of distance used in astronomy to measure how far away stars and galaxies are from Earth. One parsec is approximately 3.26 light-years, which means it’s the distance at which one astronomical unit (the average distance from the Earth to the Sun) subtends an angle of one arcsecond. This measurement helps astronomers understand the vastness of space and the positions of celestial objects. The term "parsec" comes from combining "parallax" and "arcsecond." When astronomers observe a star from two different points in Earth's orbit, they can measure its apparent movement against more distant stars. This method, known as stellar parallax, allows them to calculate the star's distance in parsecs, providing a clearer picture of our universe's structure