meteortropism: an effect of climate on biological processes (as the effect on joint pains etc.)
tropism: an involuntary orienting response; positive or negative reaction to a stimulus source
potlatch: a ceremonial feast held by some Indians of the northwestern coast of North America (as in celebrating a marriage or a new accession) in which the host gives gifts to tribesmen and others to display his superior wealth (sometimes, formerly, to his own impoverishment)