A cylindrical telescope is a telescope with cylindrical optical elements rather than the typical circularly-symmetric. It can be cylindrical lenses or reflectors, i.e., the same cross-sectional shape along a dimension.
Radio telescopes have been developed like this, typically using phase information to electronically (possibly digitally) disentangle signals along the one dimension, by the same principles as used for phased arrays.
One example cylindrical radio telescope, Ooty Radio Telescope, can be physically aimed across one dimension, tilting a long cylindrical reflector using an equatorial mount, able to do this for being located near the equator. Another example, Canadian Hydrogen Intensity Mapping Experiment, is non-steerable, with fixed mounting, using the Earth's rotation to scan all the celestial sphere viewable from its location. In both cases, they benefit from the lower construction costs by reducing the structures needed to aim.