Definition of photonegativity in US English:

photonegativity

noun

Zoology
  • Tendency to avoid or move away from light.

Origin

1920s; earliest use found in American Naturalist. From photo- + negativity, after photonegative.

Pronunciation

photonegativity

/ˌfəʊtəʊnɛɡəˈtɪvɪti/