The iterative aspect (abbreviated ITER), also called "semelfactive", "event-internal pluractionality", or "multiplicative", is a grammatical aspect that expresses the repetition of an event observable on one single occasion, as in 'he knocked on the door', 'he coughed', 'she is drumming', etc.  It is not to be confused with frequentative aspect and habitual aspect, which both signal repetition over more than one occasion.
Other authors have reserved the term "semelfactive" for this mono-occasional repetition, and defined iterative aspect as denoting 'several' repetitions over more than one occasion, as opposed to the 'frequent' repetitions conveyed by frequentative aspect.
- Smith, C. S. (1991). The parameter of aspect. Dordrecht: Kluwer, p28.
- Bertinetto, Pier Marco, and Alessandro Lenci. 2012. "Habituality, Pluractionality, and Imperfectivity." In The Oxford Handbook of Tense and Aspect, edited by Robert I. Binnick, 852-880. Oxford: Oxford University Press.
- Tatevosov, Sergej. 2002. "The parameter of actionality." Linguistic Typology 6: pp317-401.
- Bhat, D.N.S. 1999. The prominence of tense, aspect and mood. Benjamins. pp53ff
- p160 in Bybee, J., R. Perkins, & W. Pagliuca, The Evolution of Grammar: Tense, Aspect, and Modality in the Languages of the World. Chicago: The University of Chicago Press.
- p236 in S.C. Dik. 1997. The Theory of Functional Grammar, part I The Structure of the Clause. Berlin: Mouton.