What is "sleeper shark"

Nurse \Nurse\ (n[^u]rs), n. [OE. nourse, nurice, norice, OF. nurrice, norrice, nourrice, F. nourrice, fr. L. nutricia nurse, prop., fem. of nutricius that nourishes; akin to nutrix, -icis, nurse, fr. nutrire to nourish. See Nourish, and cf. Nutritious.]

1. One who nourishes; a person who supplies food, tends, or brings up; as:

   1. A woman who has the care of young children; especially, one who suckles an infant not her own.

   2. A person, especially a woman, who has the care of the sick or infirm.

2. One who, or that which, brings up, rears, causes to grow, trains, fosters, or the like.

   The nurse of manly sentiment and heroic enterprise.
   --Burke.

3. (Naut.) A lieutenant or first officer, who is the real commander when the captain is unfit for his place.

4. (Zo["o]l.)

   1. A peculiar larva of certain trematodes which produces cercari[ae] by asexual reproduction. See Cercaria, and Redia.

   2. Either one of the nurse sharks. Nurse shark. (Zo["o]l.)

      1. A large arctic shark ( Somniosus microcephalus), having small teeth and feeble jaws; -- called also sleeper shark, and ground shark.

      2. A large shark ( Ginglymostoma cirratum), native of the West Indies and Gulf of Mexico, having the dorsal fins situated behind the ventral fins.

         To put to nurse, or To put out to nurse, to send away to be nursed; to place in the care of a nurse.

         Wet nurse, Dry nurse. See Wet nurse, and Dry nurse, in the Vocabulary.