Sentence:  The bright star Aldebaran is to be occulted by the moon on December 20th, at about 5 o'clock pm. Aldebaran is said to be eight hundred and eighty times the mass of the sun, with a diameter of over 8,000,000 miles; a distance so great that a meteor traveling at the rate of thirty miles per second, would require over three days to cross the disk of the star. Yet, notwithstanding the immense volume, the <WSD>accultation</WSD> will occur in a moment, so great is the distance of the star from us, and will continue for about one hour and eight minutes. 
Meaning of the word marked with <WSD> tags:  An astronomical event that occurs when one celestial object is hidden by another celestial object that passes between it and the observer when the nearer object appears larger and completely hides the more distant object.