A sketch is a rapidly executed freehand drawing that is not usually intended as a finished work. Artists usually sketch to record something that they see; for later use in their creations. Sketches can be made in any drawing medium. The term is most often applied to graphic work executed in a dry media such as pencil, charcoal or pastel.
The term sketchbook refers to a book of blank paper on which an artist can, (or has already) drawn sketches.
Street-artists in popular tourist areas sketch portraits within minutes. These are as such the more finished versions of sketching. Some artists too render fully finished sketches with pencil or pen-and-ink; mostly in the genres of landscapes and still-life.