As others have said, this will depend on the specifics of your case (i.e. the employment and other agreements between you and the company).
However, you implied a question about single/double trigger. If your contract mentions single trigger vesting, it _typically_ means that some/all of your equity vests on a sale of all or substantially all of the company. Double trigger vesting is similar, but would require a second event (usually your position being no longer available, e.g. if you were CTO and the acquirer didn't need two CTOs) to trigger vesting.
However, you implied a question about single/double trigger. If your contract mentions single trigger vesting, it _typically_ means that some/all of your equity vests on a sale of all or substantially all of the company. Double trigger vesting is similar, but would require a second event (usually your position being no longer available, e.g. if you were CTO and the acquirer didn't need two CTOs) to trigger vesting.