Charles Buck Theological Dictionary 
Heads of families; a name applied chiefly to those who lived before Moses, who were both priests and princes, without peculiar places fitted for worship, Acts 2:29; Acts 7:8-9 . Hebrews 7:4 . Patriarchs among Christians, are ecclesiastical dignitaries, or bishops, so called from their paternal authority in the church. The power of patriarchs was not the same in all, but differed according to the different customs of countries, or the pleasures of kings and councils. Thus the patriarch of Constantinople grew to be a patriarch over the patriarchs of Ephesus and Caesarea, and was called the (Ecumenical and Universal Patriarch; and the patriarch of Alexandria had some prerogatives which no other patriarch but himself enjoyed; such as the right of consecrating and approving of every single bishop under his jurisdiction. The patriarchate has ever been esteemed the supreme dignity in the church: the bishop had only under him the territory of the city of which he was bishop; the metropolital superintended a province, and had for suffragans the bishops of his province; the primate was the chief of what was then called a diocess, and had several metropolitans under him; and the patriarch had under him several diocesses, composing one exarchate, and the primates themselves were under him. Usher, Pagi, De Marca, and Morinus, attribute the establishment of the grand patriarchates to the apostles themselves, who, in their opinion, according to the description of the world then given by geographers, pitched on three principal cities in the three parts of the known world, viz. Rome in Europe, Antioch in Asia, and Alexandria in Africa: and thus formed a trinity of patriarchs.
Others maintain, that the name patriarch was unknown at the time of the council of Nice; and that for a long time afterwards patriarchs and primates were confounded together, as being all equally chiefs of diocesses, and equally superior to metropolitans, who were only chiefs of provinces. Hence Socrates gives the title patriarch to all the chiefs of diocesses, and reckons ten of them. In deed, it does not appear that the dignity of patriarch was appropriated to the five grand sees of Rome, Constantinople, Alexandria, Antioch, and Jerusalem, till after the council of Chalcedon, in 451; for when the council of Nice regulated the limits and prerogatives of the three patriarchs of Rome, Antioch, and Alexandria, it did not give them the title of patriarchs, though it allowed them the pre-eminence and privileges thereof: thus when the council of Constantinople adjudged the second place to the bishop of Constantinople, who, till then, was only a suffragan of Heraclea, it said nothing of the patriarchate. Nor is the term patriarch found in the decree of the council of Chalcedon, whereby the fifth place is assigned to the bishop of Jerusalem; nor did these five patriarchs govern all the churches. There were besides many independent chiefs of diocesses, who, far from owning the jurisdiction of the grand patriarchs, called themselves patriarchs, such as that of Aquileia; nor was Carthage ever subject to the patriarch of Alexandra. Mosheim (Eccles. Hist. vol. 1: p. 284.) imagines that the bishops who enjoyed a certain degree of pre-eminence over the rest of their order, were distinguished by the Jewish title of patriarchs in the fourth century.
The authority of the patriarchs gradually increased till about the close of the fifth century: all affairs of moment within the compass of their patriarchates came before them, either at first hand, or by appeals from the metropolitans. They consecrated bishops; assembled yearly in council the clergy of their respective districts; pronounced a decisive judgment in those cases where accusations were brought against bishops; and appointed vicars or deputies, clothed with their authority, for the preservation of order and tranquility in the remoter provinces. In short, nothing was done without consulting them, and their decrees were executed with the same regularity and respect as those of the princes. It deserves to be remarked, however, that the authority of the patriarchs was not acknowledged through all the provinces without exception. Several districts, both in the eastern and western empires, were exempted from their jurisdiction. The Latin church had no patriarchs till the sixth century; and the churches of Gaul, Britain, &c. were never subject to the authority of the patriarch of Rome, whose authority only extended to the suburbicary provinces. There was no primacy, no exarchate, nor patriarchate, owned here; but the bishops, with the metropolitans governed the church in common. Indeed, after the name patriarch became frequent in the West, it was attributed to the bishop of Bourges and Lyons; but it was only in the first signification, viz. as heads of diocesses. Du Cange says, that there have been some abbots who have borne the title of patriarchs.
Fausset's Bible Dictionary 
Heads of races, tribes, clans, and families. Abraham ( Hebrews 7:4), Jacob's sons ( Acts 7:8-9), David ( Acts 2:29). The" patriarchal system" before Moses developed itself out of family relations, before the foundation of nations and regular governments. The "patriarchal dispensation" is the covenant between God and the godly seed, Seth, Noah, Abraham, and their descendants; the freedom of intercourse with God is simple and childlike, as contrasted with the sterner aspect of the Mosaic dispensation. It is the innocence of childhood, contrasted with the developed manhood of our Christian dispensation. The distinction between the seed of the woman and that of the serpent appears in God's revealing Himself to the chosen as He did not to the world; hence their history is typical ( Galatians 4:21-31; Hebrews 7:1-7; Matthew 24:37-39; Luke 17:28-32; Romans 9:10-13).
Yet God is revealed as God not merely of a tribe, but of all the earth ( Genesis 18:25). All nations were to be blessed in Abraham. The Gentile Pharaoh and Abimelech have revelations. God is called "almighty" ( Genesis 17:1; Genesis 28:3; Genesis 35:11). Melchizedek, of Canaanite Salem, is His king priest, and He punishes Canaanite Sodom and Gomorrah. Authority is grounded on paternal right, its natural ground and source, even as God is the common Father of both patriarch and children. The birthright is the privilege of the firstborn, but requiring the father's confirmation. Marriage is sacred ( Genesis 34:7; Genesis 34:13; Genesis 34:31; Genesis 38:24). Intermarriage with idolaters is treason to God and the chosen seed ( Genesis 26:34-35; Genesis 27:46; Genesis 28:1; Genesis 28:6-9). The patriarchs severally typify Him in whom all their several graces meet, without blemish.
Hawker's Poor Man's Concordance And Dictionary 
This name is not of the Hebrew, but Greek language. The title is chiefly confined to the heads of families before the law; for when we speak of the patriarchs without particularizing by name it is generally understood of those before the flood, and afterwards confined to the persons and families of Abraham, Issac, Jacob, and their tribe. The Hebrews rather call them princes than patriarchs, and distinguish all of this description by the general appellation Roshe Aboth. As to the name of patriarch given to the Greek church in modern times, this is altogether fanciful, and not derived from any authority in Scripture.
Watson's Biblical & Theological Dictionary 
This name is given to the ancient fathers, chiefly those who lived before Moses, as Adam, Lamech, Noah, Shem, &c, Abraham, Isaac, Jacob, the sons of Jacob, and heads of the tribes. The Hebrews call them princes of the tribes, or heads of the fathers. The name patriarch is derived from the Greek patriarcha, "head of a family."
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
Bibliography Information McClintock, John. Strong, James. Entry for 'Patriarchs'. Cyclopedia of Biblical, Theological and Ecclesiastical Literature. https://www.studylight.org/encyclopedias/eng/tce/p/patriarchs.html. Harper & Brothers. New York. 1870.