Syzygy (n.) The coupling together of different feet; as, in Greek verse, an iambic syzygy.
Syzygy (n.) Any one of the segments of an arm of a crinoid composed of two joints so closely united that the line of union is obliterated on the outer, though visible on the inner, side.
Syzygy (n.) The immovable union of two joints of a crinoidal arm.