July 23, 1997

thigmotropic

"Thigmotropic" is a word that's supposed to mean "fond of pressure or contact," but I would like a more thorough definition, if possible.

Thigmotropism is a biological term meaning 'oriented growth of an organism in response to mechanical contact, as a plant tendril coiling around a string support'. The adjectival form thigmotropic means pretty much 'of, pertaining to, or exhibiting thigmotropism'.

The word is formed from the Greek word thígma 'touch' and the English tropism 'the orientation of an organism toward or away from a stimulus, as light'. It is first found in scientific literature around 1900.

Thigmotropic seems to be pretty much restricted to science. It's not hard to imagine a figurative use meaning 'fond of touch', as you suggest, but I'm not aware of any such use. There's probably an example in Pynchon somewhere. I have, on the other hand, seen a figurative example of the related thigmotaxis 'movement of an organism in response to contact with a solid': "The cat's sleeping in my chair again, honey--pass me the broom and I'll try a little thigmotaxis." This is from a humorous book of interesting words, but it works for me.