Architecture (Latin architectura, after the Greek ἀρχιτέκτων – arkhitekton – from ἀρχι- "chief" and τέκτων "builder, carpenter, mason") is both the process and the product of planning, designing, and constructing buildings and other physical structures. Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements.

"Architecture" can mean:

•     A general term to describe buildings and other physical structures.
•     The art and science of designing buildings and (some) nonbuilding structures.
•     The style of design and method of construction of buildings and other physical structures.
•     The practice of the architect, where architecture means offering or rendering professional services in connection with the design and construction  of buildings, or built environments.
•     The design activity of the architect, from the macro-level (urban design, landscape architecture) to the micro-level (construction details and furniture).

Architecture has to do with planning, designing and constructing form, space and ambience to reflect functional, technical, social, environmental and aesthetic considerations. It requires the creative manipulation and coordination of materials and technology, and of light and shadow. Often, conflicting requirements must be resolved. Architecture also encompasses the pragmatic aspects of realizing buildings and structures, including scheduling, cost estimation and construction administration. Documentation produced by architects, typically drawings, plans and technical specifications, defines the structure and/or behavior of a building or other kind of system that is to be or has been constructed.

Paraphrased from Wikipedia: http://en.wikipedia.org/wiki/Architecture