[pre.sump.tion] n [ME presumpcioun, fr. OF presumption, fr. LL & L; LL praesumption-, praesumptio presumptuous attitude, fr. L, assumption, fr. praesumere] (13c) 1: presumptuous attitude or conduct: audacity
2. a: an attitude or belief dictated by probability: assumption b: the ground, reason, or evidence lending probability to a belief
3: a legal inference as to the existence or truth of a fact not certainly known that is drawn from the known or proved existence of some other fact