Boyd’s Bible Dictionary:
(elbow). Distance from the elbow to end of the middle finger, or about 21.8 inches (Gen. 6:15; 1 Sam. 17:4).
Concise Bible Dictionary:
Many efforts have been made to ascertain the length of this measure, from which others could be calculated. Its name signifies that it was the measure of a man’s arm from the elbow to the tip of the middle finger. Of course this would vary in different persons, and some measure would have to be taken as a standard. In the Palestine Exploration this subject has not been lost sight of. Many tombs have been measured, but they give no definite result. The inscription found in the Siloam tunnel states the length of the tunnel to be 1,200 cubits, as read by Major Condor; but 1,000 cubits as interpreted by Professor Sayce. Doubtless only a round number is intended. Its length has been found to be 1,750 feet; which makes the cubit by the two interpretations, 17.5 or 21 inches. There are however many other measurements that seem to give a cubit of 16 inches. Many of the ancient stones in the base of the temple area, the breadth of the pilasters found in the north-western corner of the area, together with their distances apart, and also the Galilean synagogues, all give a measure of 16 inches. “Quarterly Statement,” Jan., 1894.
In Ezekiel 41:8 we read of a “great cubit,” and in the commencement of the description of the future temple the reed is described as being “six cubits long by the cubit and a handbreadth” (Ezek. 40:5). This agrees with the former passage which speaks of “a full reed of six great cubits.” From this we gather that there was an ordinary cubit, and a great cubit, the difference being a handbreadth, which is accounted to be the same as the palm, a sixth of a cubit. In Deuteronomy 3:11 we find a cubit “after the cubit of a man”; and in 2 Chronicles 3:3, a cubit “after the first measure,” or “former” or “older” measure. From these passages it is clear that there were different measures called the cubit. The 16 inches above named may have been the shortest, but what was the length of the longest is quite uncertain. See WEIGHTS and MEASURES.
Strong’s Dictionary of Hebrew Words:
Meaning:
from an unused root apparently meaning to grasp; properly, a span
From Manners and Customs of the Bible:
Exodus 25:10. Two cubits and a half shall be the length thereof, and a cubit and a half the breadth thereof, and a cubit and a half the height thereof.
The word cubit is derived directly from the Latin cubitus, the lower arm. The Hebrew word is ammah, the mother of the arm, that is, the forearm. It is evidently a measure taken from the human body; as were other measures of length among the Hebrews and other nations. There seem to be two kinds of cubits, and some say three kinds, mentioned in Scripture. In Deuteronomy 3:11, we read of “the cubit of a man.” In 2 Chronicles 3:3, “cubits after the first [or old] measure” are spoken of. In Ezekiel 41:8, we are told of “great cubits,” each one of which, according to Ezekiel 40:5, “measured a cubit and a handbreadth.” Some writers suppose these to represent three different measures of length; while others regard the first and second as identical, thus making but two kinds of cubits. Whether two or three cannot now be determined. It is no easier to decide as to the length of any one of the cubits named. Various estimates of the Mosaic cubit have been given, varying from twelve inches to twenty-two. The ancient Egyptian cubit was nearly twenty-one inches, which some of the best authorities now estimate as the length of the Mosaic. Other authorities, however, equally worthy of consideration, claim that the length of the Mosaic cubit, as applied to the Tabernacle and Temple, was eighteen inches; and that the Jews did not use the cubit of twenty-one inches—which was Babylonian as well as Egyptian—until after the captivity.