Greek ἐπιβολή τῆς διανοίας (epibolē tēs dianoias)
The act of attention by which the mind (or a sense) fixes on an impression and grasps it. Later Epicureans, according to Diogenes Laertius, added the "focusing of the mind upon images" to the criteria of truth.
1. Key Texts
Quote from Diogenes Laertius 10.31Thus Epicurus, in the Canon ('Yardstick'), says that sensations, preconceptions and feelings are the criteria of truth. The Epicureans add the 'focusings of thought into an impression.' (tr. Long & Sedley)