citta-ekāgratā  (Sanskrit; Pāli, citta-ekaggatā). Literally, ‘one-pointedness of mind’, a meditational state of equipoise in which the mind is focused on a single object. This may be a visual image, a sound, a concept, or other mental representation.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)