What's a Cursor?

Miss Macias: "Students, who can tell me what a 'cursor' is?"

Student: [Shoots arm into the air and waves it frantically]

Miss Macias: "Yes, student?"

Student: [In a most serious tone] "It's a person who says bad words."

Miss Macias: uhhh...hmmm... [thinking, "how could I fix that one?"]