A trollsona refers to a person's fantroll version of themself. According to Calliope, a trollsona is “...is the profile of a fictional troll which [one enjoys] pretending to be.”
Within Homestuck, Calliope has a canonical trollsona named Callie Ohpeee. Her trollsona is a lime blood, and Calliope says she has a hard drive nearly full of artwork and writings on the character. It is under this form that Calliope choose to meet Roxy Lalonde as for the first time in person.
Later, Calliope helped Jade Harley and Jane Crocker make trollsonas as well.