disease, X grievous, (that are) sick(-ness)

Boyd’s Bible Dictionary:

(uneasy). Visitations of plagues and pestilences frequent in Bible lands (Gen. 7-8; Ex. 12:21-2921Then Moses called for all the elders of Israel, and said unto them, Draw out and take you a lamb according to your families, and kill the passover. 22And ye shall take a bunch of hyssop, and dip it in the blood that is in the bason, and strike the lintel and the two side posts with the blood that is in the bason; and none of you shall go out at the door of his house until the morning. 23For the Lord will pass through to smite the Egyptians; and when he seeth the blood upon the lintel, and on the two side posts, the Lord will pass over the door, and will not suffer the destroyer to come in unto your houses to smite you. 24And ye shall observe this thing for an ordinance to thee and to thy sons for ever. 25And it shall come to pass, when ye be come to the land which the Lord will give you, according as he hath promised, that ye shall keep this service. 26And it shall come to pass, when your children shall say unto you, What mean ye by this service? 27That ye shall say, It is the sacrifice of the Lord's passover, who passed over the houses of the children of Israel in Egypt, when he smote the Egyptians, and delivered our houses. And the people bowed the head and worshipped. 28And the children of Israel went away, and did as the Lord had commanded Moses and Aaron, so did they. 29And it came to pass, that at midnight the Lord smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon; and all the firstborn of cattle. (Exodus 12:21‑29); 2 Kings 19:3535And it came to pass that night, that the angel of the Lord went out, and smote in the camp of the Assyrians an hundred fourscore and five thousand: and when they arose early in the morning, behold, they were all dead corpses. (2 Kings 19:35); 1 Chron. 21:1212Either three years' famine; or three months to be destroyed before thy foes, while that the sword of thine enemies overtaketh thee; or else three days the sword of the Lord, even the pestilence, in the land, and the angel of the Lord destroying throughout all the coasts of Israel. Now therefore advise thyself what word I shall bring again to him that sent me. (1 Chronicles 21:12); Acts 12:2323And immediately the angel of the Lord smote him, because he gave not God the glory: and he was eaten of worms, and gave up the ghost. (Acts 12:23)). Principal bodily diseases were, ophthalmia, leprosy, brain and malarial fevers, lung disorders.

Concise Bible Dictionary:

There are four Hebrew words and four Greek words so translated, but, like the English word, they do not specify the nature of the complaint. God promised to Israel that if they would be obedient He would take away from them all sickness, and would put upon them none of the evil diseases of Egypt which they had known (Deut. 7:1515And the Lord will take away from thee all sickness, and will put none of the evil diseases of Egypt, which thou knowest, upon thee; but will lay them upon all them that hate thee. (Deuteronomy 7:15)). When the Lord was on earth He healed every sickness and every disease among the people (Matt. 9:3535And Jesus went about all the cities and villages, teaching in their synagogues, and preaching the gospel of the kingdom, and healing every sickness and every disease among the people. (Matthew 9:35)). On the ground of obedience they failed to attain freedom from diseases, but their Messiah healed them all in grace. See the various names of the specific diseases, as FEVER.

Strong’s Dictionary of Hebrew Words:

Number:
8463 (find all occurrences in KJV Bible)
Transliteration:
tachaluw’
Phonic:
takh-al-oo’
Meaning:
or tachalui {takh-al-oo'}; from 2456; a malady
KJV Usage:
disease, X grievous, (that are) sick(-ness)