1900, from thigmo-, combining form meaning "touch," from Greek thigma "touch" + tropism.
Entries linking to thigmotropism
tropism n.
1899, "tendency of an animal or plant to turn or move in response to a stimulus," 1899, abstracted from geotropism or heliotropism, with the second element taken in an absolute sense; ultimately from Greek tropos "a turning" (from PIE root *trep- "to turn").