Input (grade 13): The Tropic of Capricorn is so named because about 2,000 years ago the sun was entering the constellation Capricornus (capricorn is Latin for goat horn) at the December solstice.
Output (grade 12): The Tropic of Capricorn is named because about 2000 years ago the sun was entering the constellation Capricornus on the December solstice.