n :  a sparsely but widely distributed poisonous metallic element that resembles lead in physical properties and is used chiefly in the form of compounds in photoelectric cells or as a pesticide - symbol Tl - see ELEMENTtable   .
 
 
 
Similar sounding terms:  thu·li·um 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2004.