praesentia

Praesentia, praesentiae, f., first declension, built on praesens, praesentis, the present participle of adsum, "be at hand". So it is the state of being there, and by an easy step the time that is here now, the present.

Two traps. First, praesentia is also the neuter plural of the adjective praesens, so a bare praesentia in a text may mean "present things, present circumstances" rather than "presence"; the verb it agrees with usually settles it. Second, classical in praesentia is adverbial and means "for the moment, as things stand", not "in the presence of" - for that a Roman writes coram with the ablative. The medieval corpus spells it presencia and presenciam, with the ae flattened to e and ti softened to ci, which is what you will actually meet on the page.