iCalamus is a frame-oriented layout and DTP application for macOS which has been developed by the German software company invers Software. The name iCalamus derives from the software Calamus by the same manufacturer but neither offers document compatibility nor shares a single line of source code with the latter. (Calamus derives from the Latin name of a writing instrument made of reeds; see Kalamos.) In April 2018 iCalamus was acquired by Lemke Software, makers of GraphicConverter.