The hazels (Corylus) are a genus of deciduous trees and large shrubs native to the temperate Northern Hemisphere. The genus is usually placed in the birch family Betulaceae, though some botanists split the hazels (with the hornbeams and allied genera) into a separate family Corylaceae.

They have simple, rounded leaves with double-serrate margins. The flowers are produced very early in spring before the leaves, and are monoecious, with single-sex catkins, the male catkins are pale yellow and 5–12 cm long, and the female ones are very small and largely concealed in the buds, with only the bright-red, 1- to 3-mm-long styles visible. The seeds are nuts 1–2.5 cm long and 1–2 cm diameter, surrounded by an involucre (husk) which partly to fully encloses the nut.

The shape and structure of the involucre, and also the growth habit (whether a tree or a suckering shrub), are important in the identification of the different species of hazel.

Male flowers of common hazel in early spring

Leaves and nuts of Turkish hazel: note the spiny involucres (husks) surrounding the nuts

A television program (usually television programme outside North America), also called television show, is a segment of content intended for broadcast on television. It may be a one-time production or part of a periodically recurring series. A single program in a series is called an episode.

A television series that is intended to comprise a limited number of episodes is usually called a miniseries or serial. Series without a fixed length are usually divided into seasons or series, yearly or biannual installments of new episodes. While there is no defined length, US industry practice tends to favor longer seasons than those of some other countries.

A one-time broadcast may be called a "special", or particularly in the UK a "special episode". A television movie ("made-for-TV movie" or television film), is a film that is initially broadcast on television rather than released in cinemas or direct-to-video, although many successful TV movies are later released on DVD.

A program can be either recorded—as on video tape or other various electronic media forms—or considered live television.

series (singular/plural) may refer to anything of a serial form:

See also: sequence