Plus or minus Definition 1 of 2Pro Tip 1/3Estimation Clue Indicates rough measurement or estimate, not an exact number. The room was 15 square meters, plus or minus. Pro Tip 2/3Flexibility Allowed Shows that there's some leeway or tolerance in the given value. Please be there at 8 PM, plus or minus 10 minutes. Pro Tip 3/3Conversational Use Used informally to express a small variation might occur. I'll need plus or minus five volunteers for this task.