Webster's English Dictionary

Enter the word to look up:

tropism

tro.pism \'tro--.piz-*m, 'tra:p-.iz-\ \tro--'pis-tik, tra:-\ n [ISV 
   -tropism] 1a: involuntary orientation by an organism or one of its parts 
   that involve s turning or curving and is a positive or negative response to 
   a source of stimulation 1b: a reflex reaction involving such movement  2: 
   an innate tendency to react in a definite manner to stimuli  - tro.pis.tic 
   aj