Reflections on the terms stochastic and non-stochastic as currently used in radiological protection.

The meanings, past and present, of the word stochastic are discussed and related to the way in which "stochastic" and "non-stochastic" may be used to describe the categories of biological damage from ionizing radiation. "Haplocytic" and "polycytic" are suggested as alternatives: these terms allow a classification according to the numbers of cells involved initially and, therefore, according to the basic mechanisms. For more speculative concepts relating to carcinogenesis the word "syncytic" is suggested, together with some potentially useful terms derived from it.