adventitious

/ˌæd.vɛnˈtɪʃ.əs/
adjective
  1. Happening by chance or accident; not planned or expected.
    • Their meeting was entirely adventitious, a happy coincidence.
    • Adventitious sounds in the recording turned out to be birds outside.
    • The discovery of penicillin was an adventitious event in a lab.
  2. In biology, arising from an unusual or unexpected place, such as roots growing from stems or leaves.
    • Ivy produces adventitious roots that cling to walls.
    • The plant spread through adventitious shoots from its roots.
    • Adventitious buds can form on tree trunks after injury.
What does "adventitious" mean? | whatsthatwordmean | whatsthatwordmean