Cubit (in Heb. אִמָּה, ammah', lit. mother, i.e. of the arm, the fore-arm; Greek πῆχυς, an ell) is a word derived immediately from the Latin cubitus, the lower arm. The length of the cubit has varied in different nations and at different times. Derived as the measure is from a part of the human body, and as the human stature has been of very dissimilar length, the cubit must of necessity have been various. The lower arm, moreover, may take in the entire length from the elbow to the tip of the third or longest finger, or it may be considered as extending from the elbow merely to the root of the hand at the wrist, omitting the whole length of the hand itself. If the definition of Celsus (8. 1) is taken, and the cubit is identified with ,the ulna, the under and longer of the two bones of which the arm consists, still a fixed and invariable measure is not gained. That the cubit among the Hebrews was derived as a measure from the human body is clear from De 3:11 — "after the cubit of a man" (אִמִּת אַישׁ, see Bottcher, Proben alttest. Schrift. p. 288). But it is difficult to determine whether this cubit was understood as extending to the first or the end of the third finger. As, however, the latter seems most natural, since men, when ignorant of anatomy, and seeking in their own frames standards of measure, were likely to take both the entire foot and the entire fore-arm, the probability is that the longer was the original cubit, namely, the length from the elbow to the extremity of the longest finger. The: Egyptian cubit, which it is likely the Hebrews would adopt, consisting of six hand- breadths, is found on the ruins of Memphis (Journal des Savans, 1822, Nov., Dec.; comp. Herod. 2:149). The Rabbins also (Mishna, Chelim, 17:9) assign six hand-breadths to the Mosaic cubit. By comparing Josephus (Ant. 3, 6,5) with Ex 25:10, it will, moreover, be found that the weight of his authority is in the same scale. According to him, a cubit is equal to two spans. Now a span is equal to three hand-breadths (Schmidt, Bibl. Mathemat. p. 117; Eisen-Schmidt, De Ponderibus, p. 110); a cubit, therefore, is equal to six hand-breadths, The hand-breadth is found as a measure in 1Ki 7:26; comp. Jer 3:21. In the latter passage the finger-breadth is another measure. The span also occurs Ex 28:16. So that, it appears, measures of length were, for the most part, borrowed by the Hebrews from members of the human body. Still no absolute and invariable standard presents itself. If the question, What is a hand or finger-breadth? be asked, the answer can be only an approximation to fact. If, however, the palm or hand-breadth be taken at 3 inches, then the cubit will amount to 21 inches. In addition to the common cubit, the Egyptians had a longer one of six palms four inches. The Hebrews also have been thought to have had a longer cubit, for in Eze 40:5, we read of a cubit which seems to be an ordinary "cubit and an handbreadth;" see also Eze 43:13, where it is expressly said, "the cubit is a cubit and an hand-breadth." The prophet has been supposed to refer here to the then current Babylonian cubit, a measure which it is thought the Jews borrowed during the period of their captivity. The Rabbins make a distinction between the common cubit of five hand-breadths and the sacred cubit of six hand-breadths-a distinction which is held to be insufficiently supported by De Wette (Archaologie, p. 178). Consult Lamy, De Tabernaculo, c. 8; Carpzov, Apparat. p. 676. — Kitto, s.v. An ancient Egyptian cubit now in the Royal Museum of Paris measures 20.484 inches. The Hebrew cubit, according to Bishop Cumberland and M. Pelletier, is twenty-one inches; and the Talmudists observe that the Hebrew cubit (meaning probably the longer or sacred measure) was larger by one quarter than the Roman, which would make it contain 21.843 inches. Many writers fix it at eighteen inches, confounding it with the Greek and Roman measure of a foot and a half. The most approved computation assigns each kind of Jewish cubits the same length as the corresponding Egyptian namely, 20.24 inches for the ordinary one, and 21.888 for the sacred, which is confirmed by the mean length of several ancient cubits marked on the Egyptian monuments (Wilkinson's Anc. Egyptians, 2d series, 1:30), by a comparison of the dimensions of the Pyramids with those given in ancient authorities (Vyse's Pyramids of Gizeh, 3, 104, 105), and which we shall find to correspond remarkably with the Talmudical statement of the circuit of the Temple. In a later edition of his Ancient Egyptians, however ("Popular Account," 2:258), Wilkinson makes the ordinary Egyptian cubit to have consisted of seven palms or twenty-eight digits, and gives nine exact computations of its length, varying from 20.4729 to 20.7484 inches, which yield an average of 20.6169 inches; and he states the cubit on the Nilometer at Elephantine, from actual measurement, to be 20.625 inches.
This last is perhaps the most accurate dimension attainable for the standard cubit. (See Bockh, Metrol. Uitersuch. Berl. 1838, p. 12; Thenius, in the Stud. u. Krit. 1846, 1:770; 2:299; Lepsius, Die alt-dgyptische Elle, Berl. 1865.) SEE METROLOGY.
In Jg 3:16, the term translated "cubit" is in the original גֹּמֶר, go'med (literally, a cut), a rod or staff, as the measure of a cubit. In the New Testament our Lord characteristically employs the term cubit (Mt 27:6; Lu 12:25) for the enforcement of a moral and spiritual lesson. The term also occurs in Joh 21:8, and in Re 21:17; and in the Apocrypha (2 Maccabees 13:5). SEE MEASURE.