phototonus

[ foh-tot-n-uh s ]
/ foʊˈtɒt n əs /

noun Biology.

the normal condition of sensitiveness to light in organisms or their organs.
the irritability exhibited by cytoplasm when exposed to light of a certain intensity.

Origin of phototonus

First recorded in 1870–75; photo- + tonus

OTHER WORDS FROM phototonus

pho·to·ton·ic [foh-tuh-ton-ik] /ˌfoʊ təˈtɒn ɪk/, adjective

Words nearby phototonus

phototelegraphy, phototheodolite, phototherapeutics, phototherapy, photothermic, phototonus, phototopography, phototoxic, phototoxin, phototransistor, phototroph

British Dictionary definitions for phototonus

phototonus
/ (fəʊˈtɒtənəs) /

noun

the condition of plants that enables them to respond to the stimulus of light

Derived forms of phototonus

phototonic (ˌfəʊtəʊˈtɒnɪk), adjective

Word Origin for phototonus

C19: from photo- + Greek tonos tone

Medical definitions for phototonus

phototonus
[ fō-tŏt′n-əs ]

n.

The state of being sensitive to or irritated by light.

Other words from phototonus

pho′to•ton′ic (fō′tə-tŏn′ĭk) adj.