From BiblePortal Wikipedia

Watson's Biblical & Theological Dictionary [1]

In time of mourning the Jews shaved their heads, and neglected to trim their beards. The king of the Ammonites shaved off half the beards of David's ambassadors, which was the greatest insult he could offer. This will appear from the regard which the easterns have ever paid to the beard. D'Arvieux gives a remarkable instance of an Arab who, having received a wound in his jaw, chose to hazard his life rather than to suffer his surgeon to take off his beard. It was one of the most infamous punishments of cowardice in Sparta, that they who turned their backs in the day of battle were obliged to appear abroad with one half of their beard shaved, and the other half unshaved. The easterns considered the beard as venerable, because it distinguished men from women, and was the mark of freemen in opposition to slaves. It was still, in times comparatively modern, the greatest indignity that could be offered in Persia. Shah Abbas, king of that country, enraged that the emperor of Hindostan had inadvertently addressed him by a title far inferior to that of the great shah-in-shah, or king of kings, ordered the beards of the ambassadors to be shaved off, and sent them home to their master. "One of the buffoons of the bashaw," says Belzoni, "took it into his head one day, for a frolic, to shave his beard, which is no trifle among the Turks; for some of them, I really believe, would sooner have their head cut off than their beard. In this state he went home to his women, who actually thrust him out of the door; and such was the disgrace of cutting off his beard, that even his fellow buffoons would not eat with him till it was grown again."

American Tract Society Bible Dictionary [2]

The Jews shaved their beards and hair in time of mourning, repentance, or distress,  Job 1:20   Jeremiah 48:37 , and in certain ceremonial purifications,  Leviticus 14:9   Numbers 8:7 . At other times they wore them long, like other oriental nationsexcept the Egyptians, who kept their beards shaved, as we learn from Herodotus and from antique monuments. Hence Joseph shaved before he was presented to Pharaoh,  Genesis 41:14 . See Beard .

Webster's Dictionary [3]

(1): ( n.) That which is shaved off; a thin slice or strip pared off with a shave, a knife, a plane, or other cutting instrument.

(2): ( n.) The act of one who, or that which, shaves; specifically, the act of cutting off the beard with a razor.

(3): ( p. pr. & vb. n.) of Shave

Hastings' Dictionary of the New Testament [4]

See Hair, Nazirites.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [5]

(properly גָּלִח , Ξυράω ) . The ancient Egyptians were the only Oriental nation who objected to wearing the beard. Hence, when Pharaoh sent to summon Joseph from his dungeon, we find it recorded that the patriarch "shaved himself" ( Genesis 41:14). Shaving was therefore a remarkable custom of the Egyptians, in which they were distinguished from other Oriental nations, who carefully cherished the beard, and regarded the loss of it as a deep disgrace. That this was the feeling of the Hebrews is obvious from many passages (see especially  2 Samuel 10:4); but here Joseph shaves himself in conformity with an Egyptian usage, of which this passage conveys the earliest intimation, but which is confirmed not only by the subsequent accounts of Greek and Roman writers, but by the ancient sculptures and paintings of Egypt, in which the male figure is usually beardless. It is true that in sculptures some heads have a curious rectangular beard, or rather beard case attached to the chin; but this is proved to be an artificial appendage by the same head being represented sometimes with and at other times without it, and still more by the appearance of a band which passes along the jaws and attaches it to the cap on the head or to the hair. It is concluded that this appendage was never actually worn, but was used in sculpture to indicate the male character. (See Beard).

The practice of shaving. the beard and hair, and sometimes the whole body, was observed among the Hebrews only under extraordinary circumstances. The Levites on the day of their consecration, and the lepers at their purification, shaved all the hair off their bodies ( Numbers 8:7;  Leviticus 14:8-9). A woman taken prisoner in war, when she married a Jew, shaved the hair off her head ( Deuteronomy 22:12), and the Hebrews generally, and also the nations bordering on Palestine, shaved themselves when they mourned, and in times of great calamity, whether public or private ( Isaiah 7:20;  Isaiah 15:2;  Jeremiah 41:5;  Jeremiah 48:37;  Baruch 6:30). God commanded the priests not to cut their hair or beards in their mournings ( Leviticus 21:5). It may be proper to observe that, among the most degrading of punishments for: women is the loss of their hair; and the apostle hints at this ( 1 Corinthians 11:6): "If it be a shame for a woman to be shorn or shaven," etc. (See Hair).

Modern Orientals shave the head alone, and that only in the case of settled residents in towns (Van Lennep, Bible Lands, p. 517). (See Barber).

International Standard Bible Encyclopedia [6]

shāv´ing (in   Job 1:20 , גּזז , gāzaz , usually גּלח , gālaḥ  ; in  Acts 21:24 , ξυράω , xuráō ): Customs as to shaving differ in different countries, and in ancient and modern times. Among the Egyptians it was customary to shave the whole body (compare  Genesis 41:14 ). With the Israelites, shaving the head was a sign of mourning ( Deuteronomy 21:12;  Job 1:20 ); ordinarily the hair was allowed to grow long, and was only cut at intervals (compare Absalom,  2 Samuel 14:26 ). Nazirites were forbidden to use a razor, but when their vow was expired, or if they were defiled, they were to shave the whole head ( Numbers 6:5 ,  Numbers 6:9 ,  Numbers 6:18 ff; compare   Acts 21:24 ). The shaving of the beard was not permitted to the Israelites; they were prohibited from shaving off even "the corner of their beard" ( Leviticus 21:5 ). It was an unpardonable insult when Hanun, king of the Ammonites, cut off the half of the beards of the Israelites whom David had sent to him ( 2 Samuel 10:4;  1 Chronicles 19:4 ).

Shaving "with a razor that is hired" is Isaiah's graphic figure to denote the complete devastation of Judah by the Assyrian army ( Isaiah 7:20 ).