A part of speech usually expressed as a pause or hesitation; such as err, um, hmm

(obsolete) To master throughly; dominate.

(chemistry) Any compound of general formula SeOX₂ where X is a halide.

(archaic) Belonging to, or resembling, an abyss; unfathomable. / (geography) Of or belonging to the ocean depths, especially below 2000 metres (6500 ft): abyssal zone.