The Collaborative International Dictionary of English v.0.48:

lawrencium \lawrencium\ n. [from Ernest O. Lawrence, inventer of
   the cyclotron.]
   A transuranic element of atomic number 103. It was discovered
   in 1961 by bombardment of californium in a cyclotron with
   boron nuclei. Other isotopes were prepared in 1965 at Dubna.
   The atomic weight of the most stable isotope is 256, having a
   half-life of 35 seconds. Symbol Lr. --HCP61

   Syn: Lr.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Lr \Lr\ n.
   The chemical symbol for lawrencium, a transuranic element
   of atomic number 103.

   Syn: lawrencium.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

lawrencium
    n 1: a radioactive transuranic element synthesized from
         californium [syn: lawrencium, Lr, atomic number 103]