Pronounced - peri he li un
Perihelion is when Earth is closest to the sun, 91.5 million miles, instead of the average 93 million miles.
It is not the cause of our seasons.
It is when the sun looks the biggest, by about 3% and it's when Earth travels the fastest. The date varies from January 2-5, due to leap year issues.
This year it will be January 4 about 7am our time.
Happy New year.