Apple TV 4K (4th Generation), 32 GB

4K, 4-K or 4k may refer to:

• 4000 (number)
• Four kibibytes (4 × 1024 bytes, better written 4 KiB)
  • 4K disk sector size (Advanced Format)
  • 4K demoscene compo, a computer art competition using programs limited to 4 kibibytes
  • The Java 4K Game Programming Contest
• 4K resolution, a collective term for digital video formats having a horizontal resolution of approximately 4,000 pixels
  • 4K UHDTV, an ultra-high-definition television format
• 4K, the IATA airline code for Askari Aviation
• 4K, an alternative name for Cuatro Cabezas (Four Heads), an Argentine multimedia production company.
• 4K, model of Toyota K engine
• 4K, the production code for the 1976 Doctor Who serial The Brain of Morbius
• 4KScore test for prostate cancer screening
• Kenn Borek Air, a Canadian airline IATA code

An apple is a round, edible fruit produced by an apple tree (Malus spp., among them the domestic or orchard apple; Malus domestica). Apple trees are cultivated worldwide and are the most widely grown species in the genus Malus. The tree originated in Central Asia, where its wild ancestor, Malus sieversii, is still found. Apples have been grown for thousands of years in Eurasia and were introduced to North America by European colonists. Apples have religious and mythological significance in many cultures, including Norse, Greek, and European Christian tradition.

Apples grown from seed tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. For commercial purposes, including botanical evaluation, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after planting. Rootstocks are used to control the speed of growth and the size of the resulting tree, allowing for easier harvesting.

There are more than 7,500 cultivars of apples. Different cultivars are bred for various tastes and uses, including cooking, eating raw, and cider or apple juice production. Trees and fruit are prone to fungal, bacterial, and pest problems, which can be controlled by a number of organic and non-organic means. In 2010, the fruit's genome was sequenced as part of research on disease control and selective breeding in apple production.

A generation is all of the people born and living at about the same time, regarded collectively. It also is "the average period, generally considered to be about 20–⁠30 years, during which children are born and grow up, become adults, and begin to have children." In kinship, generation is a structural term, designating the parent–child relationship. In biology, generation also means biogenesis, reproduction, and procreation.

Generation is also a synonym for birth/age cohort in demographics, marketing, and social science, where it means "people within a delineated population who experience the same significant events within a given period of time." The term generation in this sense, also known as social generations, is widely used in popular culture and is a basis of sociological analysis. Serious analysis of generations began in the nineteenth century, emerging from an increasing awareness of the possibility of permanent social change and the idea of youthful rebellion against the established social order. Some analysts believe that a generation is one of the fundamental social categories in a society; others consider generation less important than class, gender, race, and education.