(chemistry) A notation for denoting the prevalence of an isotope, equal to the normalized ratio of one isotope to another in a sample relative to that same ratio in a standard.

(uncountable, optics) Interference of light caused by its reflection from both boundaries of a thin film of a transparent material. / (countable, optics) An instance of this interference.

An instance of bungee jumping.

plants that have been removed in order to improve the growth of the remainder