tropisms

Noun

tropism (countable and uncountable, plural tropisms)

1. (uncountable) The turning of an organism (chiefly a plant) or part of an organism either towards or away from a stimulus; (countable) an instance of this.
   • Orientation and tropism are synonymous expressions; that gatherings [of Paramecium] take place is a consequence of the orientation, and therefore throws no light whatever upon the tropisms. (Gatherings, however, are not always indicative of a tropism, i.e., of an orientation, but may be due to...1900 January, Walter E[ugene] Garrey, “The Effects of Ions upon the Aggregation of Flagellated Infusoria: A Dissertation Submitted to the Faculties of the Graduate Schools of Arts, Literature, and...
2. (broadly, countable) A capability or tendency for a pathogen (chiefly a virus) to infect a type of cell, tissue, organ, or host organism.
   • host tropism tissue tropism
3. (countable, figuratively) Of a person: an instinctive predilection or tendency; also (generally), a liking, a preference.
   • It is reasonable to suppose that tropism will be less conspicuous in animals which are endowed with intelligence than in others; but well-marked tropisms are still to be found among the higher animals. Gregarious animals have a positive tropism toward the members of their own flock; the dog has a...1911, Isaac A[mada] Cornelison, “Tropism”, in The Natural History of Religious Feeling: A Question of Miracles in the Soul, New York, N.Y.; London: G[eorge] P[almer] Putnam’s Sons, The Knickerbocker...