n, pl  -lae  also  -las  1  :  a small bar, rod, bundle of fibers, or septal membrane in the framework of a bodily organ or part (as the spleen)  2  :  one of a pair of longitudinally directed more or less curved cartilaginous rods in the developing skull of a vertebrate that develop under the anterior part of the brain on each side of the pituitary gland and subsequently fuse with each other and with the parachordal cartilages to form the base of the cartilaginous cranium  3  :  any of the intersecting osseous bars occurring in cancellous bone .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2004.