Rick’s question: “Are these words the same? I had build a small light display and, on the weekend, I took it apart. I announced I was unassembling it. My girlfriend said ‘no.’ I was disassembling it. I didn’t think there was a difference.”
BizWritingTip response: Sorry. I have to go with your girlfriend on this one. If you are taking something apart, you are disassembling it.
There is no such word as “unassembling.” We do have “unassembled,” which is an adjective. It refers to parts or sections that must be fitted together before you can use them, e.g., unassembled furniture.
My husband once bought me an unassembled bookcase. He spent an evening building it, but it was too big for the room. He spent the next evening disassembling it.