The clergy constitute the entire body of public servants or ministers in the Christain Church, duly set apart for their office by Consecration or Ordination (qq.v.); the remainder of the Christian community, in contradistinction to the clergy, onstitute the Laity (q.v.).
The English word "clergy" (and the French clergé, clergie) is from ecclesiastical Latin (cliricus- "clergyman, prist, clerk"; see CLERK) and is more remotely connected with the Greek klēros, "lot", which was applied to the clergy "either because they are the lot of the Lord, or else becuase the Lord himself is their lot and portion" (Jerome, Epist., lii., ANF, vi. 91; cf. Acts i. 26; Num. xviii. 20; Deut. x. 9, xviii. 2, LXX.). Another term of ecclesiastical Latin is spirituales. Paul had designated as "spiritual" certain Christians in whom the spirit of Christ manifested itself with special power (I Cor. xiv. 37; Gal. vi. 1; cf. Irenæus on I Cor. ii. 6, Hœr., V. vi. 1; Theodoret on ICor. ii. 15). The priest, according to Chrysostom ("on the Priesthood," iii. 4; NPNF, 1st ser., ix. 46), has a vocation instituted neither by "man, nor angel, nor archangel, nor any other created power, but the Paraclete himself." According to Peter Lombard (Sent., iv., dist. 4), the offis is a munus spirituale; all the seven grades of holy orders are spirituales; the ordo is "something sacred by which the power of the Spirit is imparted to the ordained." In consequence of this point of view the designation "spirituales" and its German equivalent "Geistlich" were transferred to the incumbents of the office.
–New Schaff-Herzog Encyclopedia of Religious Knowledge [Dictionary edition]