subitization en · NOUN
Etymology
From subitize + -ation.
Meanings
-
(uncountable) The process of, or act of, glancing at a group of a few objects and knowing how many there are without actually counting.
Monkeys and other animals can compute the exact number of a small set of objects at a glance without explicitly counting. The ability is called subitization.
2008 April 22, Christine Kenneally, “When Language Can Hold the Answer”, in The New York Times: