Calendar

In astronomy, revolution refers to the periodic movement by which a celestial object returns to its starting point in its orbit. Then in the 18th century, the word expressed the time it takes for the earth to travel in its orbit. This evolution is curious to say the least, since it moves the word from a spatial category to a temporal one. Even more surprisingly, the word first designated the completion of a cycle and then became synonymous with a radical change (French or Russian Revolution), this time indicating the impossibility of going back!