Define "switch"?

From what I can gather, a switch is someone who enjoys being both dominant and submissive, correct?

If so, I believe I am a switch. I love being spanked and choked by my boyfriend, and I melt whenever he calls me his dirty slut. But when I get on top this whole new fire starts inside me and I love being in control. I pull his hair and tease him endlessly.

Anyone else?