n. A shark of the family Sphyrnidæ or Zygœnidæ: so called from the great lateral expansion of the head.n. A catostomine fish, Hypentelium nigricans, having a peculiarly shaped head, which is flat above and transversely concave between the eyes, while the snout is abruptly turned down. It abounds in the fresh waters of the United States, from New York to Kansas and Alabama. It sometimes attains a length of two feet. Other names are hogsucker, stone-roller, and crawl-a-bottom.n. The umber or shadow-bird, Scopus umbretta.n. In pianoforte-making, the padded projection of the hammer which strikes against the string.