astrologyn.

Etymology: < (i) Middle French astrologie (c1243 in Old French; French astrologie : see note below on semantic history), and its etymon (ii) classical Latin astrologia science or study of celestial objects, astronomy, book on astronomy, in post-classical Latin also astrology (late 2nd or early 3rd cent. in Tertullian) < ancient Greek ἀστρολογία astronomy, in Hellenistic Greek also astrology < ἀστρολόγος astronomer (see astrologue n.) + -ία -y suffix³. Compare Old Occitan astrologia (end of the 13th cent.), Catalan astrologia (end of the 14th cent.), Spanish astrología (c1250), Portuguese astrologia (1344; 13th cent. as †estrologia), Italian astrologia (second half of the 13th cent.), also Middle Dutch arstologie (transmission error; Dutch astrologie), Middle Low German astrologīe, German Astrologie (14th cent. in Middle High German or early modern German as astrologye).In ancient Greek ἀστρολογία and ἀστρονομία were effectively synonymous, both words denoting the science of celestial objects. Influenced by the Egyptians and the Chaldeans, the Greeks of the Hellenistic period began to make calculations and predictions on the basis of astronomical observations, and the word ἀστρολογία came to be used in this sense. In Latin astrologia is used earliest (in Varro, 1st cent. b.c.) and predominantly to denote the science of celestial objects. Astronomia first appears a little later (in Seneca, 1st cent. a.d.). The first author who attempts a semantic distinction between the two Latin words is Isidore (a636). Isidore ( Origines 3. 27) defines astronomia as incorporating the positions and motions of planets and stars; he distinguishes between astrologia naturalis , the study of celestial phenomena, and astrologia superstitiosa , the practice of divination and predictions based on observations of celestial phenomena. In medieval French, and likewise in Middle English, astronomie astronomy n. is attested earlier, and originally covered the whole semantic field of the study of celestial objects, including divination and predictions based on observations of celestial phenomena. In early use in French and English, astrologie astrology n. is generally distinguished as the ‘art’ or practical application of astronomy to mundane affairs, but there is considerable semantic overlap between the two words (as also in other European languages). With the rise of modern science from the Renaissance onwards, the modern semantic distinction between astrology n. and astronomy n. gradually developed, and had become largely fixed by the 17th cent. (although compare sense 2 for later exceptions, and likewise later examples at astronomy n. 2). The word is not used by Shakespeare. With natural astrology at sense 1a compare post-classical Latin astrologia naturalis (a636 in Isidore). With judicial astrology compare Middle French, French astrologie judiciaire (1533).