Il teodolite è uno strumento ottico a cannocchiale per la misurazione degli angoli azimutali (cioè contenuti in un piano orizzontale) e zenitali (cioè contenuti in un piano verticale), usato per rilievi geodetici e topografici.[1] (https://it.wikipedia.org/wiki/Teodolite)
L'etimologia di questo strumento, di uso molto comune nella topografia, e' con mia immensa sorpresa, incerta! Ho fatto una grande rierca, trovando le piu' disparate versioni. In tutta questa ricerca, Anatoly Liberman - autore di 'An Analytical Dictionary of English Etimology: An Introduction' ha riassunto come segue nel suo blog qui citato (http://blog.oup.com/2009/05/theodolite/), le diverse interpretazioni etimologiche della parola teodolite. Le sue parole sono citate qui:
Three approaches to theodolite have been tried. 1) The word has a strong Greek look, so that attempts to decompose it into two or three Greek elements need not surprise us: thea “prospect” + delo– “make visible”; theaomai “see” + dolos “stratagem” or + dolikhos “long,” or + delos “manifest” + itus “circumference.” Or perhaps the last syllable should be understood as litos “simple; smooth” (theomai “see” + odos “path” + litos = “scanner of exact (or finely drawn) lines of direction.” Conversely, –litus may be equal to Greek lithos “stone” (compare Engl. monolith); then we obtain “stone devised as a path to good observation.” The common feature of those etymologies is the root meaning “see.” Or take obelos “pointed stick, rod, spit” (as in obelisk), transmute it into Aeolic odelos, and get odelited “graduated,” whatever, th– means (perhaps the English definite article). Still another possibility is theou + dolos “god’s counsel”: “As the astrolabe had its derivation from the Greek astro and labe, taking the stars, the inventor of the theodolite thought he could do no less that seek in that language for some equivalent for Jacob’s staff” (actually, dolos means “bait; trap”). Some of the aforementioned proposals are fanciful, while the others are not unreasonable. If –us is a spurious Latin ending, litos and lithus present no interest as putative components of theodolite. In the original edition of the OED we read: “Can it have been (like many modern names of inventions) an unscholarly formation form theomai, I view, or theo, behold, and delos, visible, clear, manifest, with a meaningless termination?” Needless to say, all the sources quoted above use Greek letters with proper accent marks. (2). “Theodelitus’…consists of a graduated circle, with a diametral [sic] bar, furnished with a couple of sights. This bar always had the name of alhidada, or alidade…. Now theodelitus has the appearance of being a participle or adjective; and may therefore seem to refer to the circle as descriptive of an adjunct. A circle with alidade: could it be possible that, in the confused method of forming and spelling words which characterised the vernacular English science of the sixteenth century, an alidated circle should become theodelited?” (Professor A. De Morgan, 1863). This hypothesis (theodolite as an Arabic word; th– as the article) had a few supporters and has been periodically revived. However, it is hopelessly convoluted and presupposes numerous changes, which are the more surprising as alhidada, an old word in English, never appeared in the garbled form reconstructed by De Morgan. Frank Chance disposed of this etymology in his typically ruthless way. (3) As early as 1865 it has been suggested that the word theodolite goes back to the proper name Theodolus. One of its bearers was active in 1685, much too late for Digges, but Theodolus’s family had a reputation for being good mathematicians (J.C.J.). Skeat, writing in 1895, did not remember the old note, for he stated: “My own guess… is quite a new one, unlike any that has ever yet been suggested. My belief is that it [the word] is derived from the personal name Theodolus, which, as every schoolboy knows, means ‘servant of God’.” Today not every schoolboy knows the meaning of Theodolus (in British public, that is, private schools of Skeat’s day, there even existed a slang word dolos “slave”), but one thing is certain: an etymologist can never be sure that his (or her) conjecture is new. At that time, Skeat had no clue to the persona of the mysterious Theodolus. However, this is the pronouncement in the last edition of his dictionary: “Generally said to be Greek. Formerly theodelitus, meaning “a circle with a graduated border; used A.D. 1571. Also theodolet, theodelet. Apparently imitated (it is not known why) from Old French theodelet, theodolet, the name of a treatise, literally ‘a work by Theodulus’.” Earnest Weekley offers a similar version of this etymology: “It is just possible that Digges, for some fantastic reason now unknown, named the instrument after the famous Old French theological poem called the Tiaudelet, translated from the Late Latin Theodulus (9 century).”
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