Hypernyms (thermometer is a kind of...): measuring device; measuring instrument; measuring system (instrument that shows the extent or amount or quantity or degree of something) Meronyms (parts of thermometer):
Noun. 1. hormone-the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect. endocrine, internal secretion. secretion-a functionally specialized substance (especially one that is not a waste) released from a gland or cell.
A tropism is a growth in response to a stimulus and an auxin is a plant hormone produced in the stem tips and roots, which controls the direction of growth. Plant hormones are used in weed killers, rooting powder and to control fruit ripening.