The principle/concept of clergy and laity is in scripture; however, the words clergy and laity are not found in scripture.
Clergy consists of ordained ministers.
How one delineates clergy and laity is largely a function of the church leadership. For example, Deacons as ordained ministers may be seen as part of the clergy (e.g., some Catholic and United Methodist Deacons) or part of the laity (e.g., National Baptist Convention USA Inc. Deacons). Indeed, some Catholic churches refer to their deacons as Reverend. Whether clergy or laity is simply an organizational/denominational choice rather than a biblical mandate as neither choice in and of itself violates any biblical principle.
This classification of clergy and laity may be based on whether one is fulltime or totally dependent on the church for income, or other factors.
Also for a Catholic Church view of Deacons in contrast to Bishops and Priests see Catholic Canon Law – What Can Deacons Do? Here we see that the Catholic Church considers the Deacon as part of the Clergy with a subset of the duties of the Bishops and Priests. Note that Deacons are ordain ministers so they satisfy the ordination criteria for clergy. Viewing Deacons as part of clergy of course is a matter of human preference as the Bible does not require an specific organizational structure as long as certain biblical principles are adhered to.
Also for a generally accepted Baptist perspective concerning pastors and deacons see Baptist Distinctives – Church Officers. However, be mindful that some of this is also a matter of human preference and may not be a biblical requirement.
To God Be the Glory!