tropism
noun
tro·pism
| \ ˈtrō-ˌpi-zəm
\
\
Definition of tropism
(Entry 1 of 2)
1a
: involuntary orientation by an organism or one of its parts that involves turning or curving by movement or by differential growth and is a positive or negative response to a source of stimulation
b
: a reflex reaction involving a tropism
2
: an innate tendency to react in a definite manner to stimuli
broadly
: a natural inclination : propensity
encouraged his tropism toward the theatrical — John Updike