واللازم هو ما ينتقل الذهن من الموضوع له إليه
A necessary concomitant is that to which the mind passes from the meaning originally assigned to the word.
An accidental personal association does not suffice. If “book” reminds someone of their desk, that memory is not thereby a logical concomitant; books do not necessarily belong on desks.
By contrast, the evenness of four is a necessary property understood in connection with the number rather than as the entire assigned meaning of its name. The precise relation of necessity matters in identifying iltizām.