Noel (also spelled Nowell or Noël) (nəʊˈɛl) is an alternative word for Christmas. It first entered the English language in the 14th century. The word comes from Middle English noel, which derives from the Old French word noël and its more common form naël. The English spelling "Noël" is taken directly from modern French, which also derives from the Old French. The ultimate Latin origin is the phrase nātālis (diēs), "(day) of birth".

The no observed adverse effect level (NOAEL) denotes the level of exposure of an organism, found by experiment or observation, at which there is no biologically or statistically significant (e.g. alteration of morphology, functional capacity, growth, development or life span) increase in the frequency or severity of any adverse effects in the exposed population when compared to its appropriate control.