/thee'euh fil"een, -in/ , n. Pharm.
a white, crystalline, poisonous alkaloid, C 7 H 8 N 4 O 2 , an isomer of theobromine, extracted from tea leaves or produced synthetically: used to relieve bronchial spasms, in the treatment of certain heart conditions, and as a diuretic.
[ 1890-95; theo -, irreg. comb. form repr. NL thea tea + -PHYLL + -INE 2 ]