Real Dictionary

monotype in American English
either of a pair of machines for casting and setting up type in separate characters on individual bodies: one, a casting machine, is controlled by a paper tape perforated on the other, a keyboard machine
the only type of its group, as a single species constituting a genus, a single genus constituting a family, etc.
noun: a brand of machine for setting and casting type, consisting of a separate keyboard for producing a paper tape containing holes in a coded pattern so that when this tape is fed into the casting unit each code evokes a unique letter cast from hot metal by a
noun: the only print made from a metal or glass plate on which a picture is painted in oil color, printing ink, or the like

monotype in British English
noun: a single print made from a metal or glass plate on which a picture has been painted
noun: any of various typesetting systems, esp originally one in which each character was cast individually from hot metal