dark formal calendar with white date week month

endar is a system for naming periods of time, typically days. These names are known as calendar dates. The dates may be based on the perceived motion of astronomical objects. A calendar is also a physical device (often paper) that illustrates the system (for example, a desktop calendar) — this is the most common usage of the word. See more at Wikipedia.org...

eneral usage, an interface is the point, area, or surface along which two substances or other qualitatively different things meet; it is also used metaphorically for the juncture between items. The word interface is sometimes (usually in technical disciplines) shortened to "i/f". The verb to interface means to interconnect two or more entities at a common point or shared boundary, or to prepare either entity for that purpose. See more at Wikipedia.org...