POSIT Meaning of POSIT in English [pos.it] vt pos.it.ed ; pos.it.ing [L positus, pp. of ponere] (1647) 1: to dispose or set firmly: fix 2: to assume or affirm the existence of: postulate 3: to propose as an explanation: suggest Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012