FOCAL a.
Belonging to,or concerning, a focus; as, a focal point. Focal distance, or length,of a lens or mirror (Opt.), the distance of the focus from the surface of the lens or mirror, or more exactly, in the case of a lens, from its optical center. --Focal distance of a telescope, the distance of the image of an object from th…
GUARANTEE v.
, etc.) to another against a specified contingency, or at all avents; to give a guarantee concerning; to engage, assure, or secure as a thing that may be depended on; to warrant; as, to guarantee the execution of a treaty. The United States shall guarantee to every State in this Union a republican form of government. C…