passim

Passim is the adverb of passus, the perfect participle of pando, "spread out", so its root sense is "in a scattered way". Two meanings shade into each other: over the whole area, everywhere, and without order, at random. The second is doing the quiet work in a phrase like passim caedere, to kill indiscriminately, where "everywhere" would miss the point.

Scholarship borrowed it whole and unchanged. A citation marked passim means the thing is scattered through the work rather than sitting on one page, and English kept the Latin form and the Latin sense. The trap is a homograph two steps back: Latin has two identical participles passus, one from pando (behind passim, and behind passus, "a pace") and one from patior, "suffer", which is behind Passion and passive. Same spelling, unrelated verbs.