noun.
An imaginary sail, set along with moon-sails, sky-gazers, and the like, jokingly assumed to be carried in the days when sail-power was the sole reliance at sea, and United States ships had the reputation of being the fastest afloat.
noun.
A triangular skysail.
noun.
A ball or missile sent high up in the air; anything which reaches or extends far into the sky.
noun.
A very tall office-building such as those first erected in various cities of the United States in the latter part of the nineteenth century. Originally from ten to fifteen stories in height, they are now occasionally built with forty stories and more.