|Noah Webster's Dictionary|
1. (n.) An incrustation over a sore, wound, vesicle, or pustule, formed by the drying up of the discharge from the diseased part.
2. (n.) The itch in man; also, the scurvy.
3. (n.) The mange, esp. when it appears on sheep.
4. (n.) A disease of potatoes producing pits in their surface, caused by a minute fungus (Tiburcinia Scabies).
5. (n.) A slight irregular protuberance which defaces the surface of a casting, caused by the breaking away of a part of the mold.
6. (n.) A mean, dirty, paltry fellow.
7. (n.) A nickname for a workman who engages for lower wages than are fixed by the trades unions; also, for one who takes the place of a workman on a strike.
8. (v. i.) To become covered with a scab; as, the wound scabbed over.
Int. Standard Bible Encyclopedia
skab, skab'-ed, skabd (yallepheth, micpachath, cappachath, verb sippach; semasia, leichen): These are generic terms for any skin disease in which there are patches of hard crusts on the surface. The commonest of these are the forms now named eczema, herpes and, perhaps, psoriasis, all of which are common in Bible lands. Milder cases in which the disease was localized and in small patches (the semasia of the Septuagint) did not render the bearer unclean, and they were to be distinguished by the priest (Leviticus 13:2, 6) from the more virulent and spreading eruptions which (Leviticus 13:7) were regarded as causes of ceremonial uncleanness. These severer forms are the leichen of Septuagint mentioned in Leviticus 21:20, which disqualified any son of Aaron from serving as a priest, and when affecting an animal rendered it unfit to be offered as a burnt offering (Leviticus 22:22). Hippocrates speaks of these cases as obstinate and persistent, and Galen believed that they might degenerate into leprosy; hence, the terms in which Aeschylus speaks of it (Choephori 281). Celsus, however, recognized that leichen was a papular eruption, not a true scab. The name yallepheth seems to have been given to it on account of the firmness of attachment of the scabs, while the term micpachath refers to its tendency to spread and cover the surface. A cognate word in Ezekiel 13:18 is the name of a large Tallith or prayer veil used by the false prophetesses in Israel (translated "kerchief"). Scabs were especially disfiguring on the head, and this infliction was threatened as a punishment on the daughters of Zion for their wanton haughtiness (Isaiah 3:17). In Middle English, "scab" is used for itch or mange, and as a term of opprobrium, as in Greene, Bacon and Bungay, 35, 1591.
Scab (7 Occurrences)
Leviticus 13:2 "When a man shall have a rising in his body's skin, or a scab, or a bright spot, and it becomes in the skin of his body the plague of leprosy, then he shall be brought to Aaron the priest, or to one of his sons, the priests: (WEB KJV JPS ASV DBY WBS YLT NAS)
Leviticus 13:6 The priest shall examine him again on the seventh day; and behold, if the plague has faded, and the plague hasn't spread in the skin, then the priest shall pronounce him clean. It is a scab. He shall wash his clothes, and be clean. (WEB KJV JPS ASV DBY WBS YLT NAS)
Leviticus 13:7 But if the scab spreads on the skin, after he has shown himself to the priest for his cleansing, he shall show himself to the priest again. (WEB KJV JPS ASV DBY WBS YLT NAS)
Leviticus 13:8 The priest shall examine him; and behold, if the scab has spread on the skin, then the priest shall pronounce him unclean. It is leprosy. (WEB KJV JPS ASV DBY WBS YLT NAS)
Leviticus 14:56 and for a rising, and for a scab, and for a bright spot; (WEB KJV JPS ASV DBY WBS YLT NAS)
Deuteronomy 28:27 The LORD will smite thee with the botch of Egypt, and with the emerods, and with the scab, and with the itch, whereof thou canst not be healed. (KJV JPS DBY WBS NAS)
Isaiah 3:17 Therefore the LORD will smite with a scab the crown of the head of the daughters of Zion, and the LORD will discover their secret parts. (KJV JPS ASV WBS YLT NAS RSV)