The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time, as a year is a unit of time equivalent to approximately 365 days.

What is the distance that light travels in one year called? Let's have some stream of consciousness first.
To answer this question, we should know that: As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). So, the answer is a light - year.