The ordinary meaning of persecution is hardship, great difficulty, affliction, or distress imposed on vulnerable racial and religious people and groups based on their belief system.
The bible meaning of tribulation is organized persecution that brings trouble to persons and people groups, denial of rights, affliction of any kind, penal sufferings imposed on the wicked and calamities like the destruction of Jerusalem in AD70 by the Romans as well as martyrdom.
Severe persecution usually leads to death and destruction of property. In some localities and times it is the route to martyrdom.
Seven years of divine judgment will precede the end of the human dispensation of grace. It corresponds to the Jewish 70th heptad. A heptad is a period of seven years. These last seven years of this era will be characterised with great tribulation judgments.
Mankind will be judged for rejecting the provision God made for the salvation of souls, the purpose being to save those who can be saved and destroy those who cannot be saved. During the seven-year tribulation period the world population will be reduced by half.
The universe will be judged because of pollution caused by angelic rebellion and the transgression of Adam and Eve. The earth will be restructured to revert to the pre-fall state.