2021 (MMXXI) was a common year starting on Friday of the Gregorian calendar, the 2021st year of the Common Era (CE) and Anno Domini (AD) designations, the 21st year of the 3rd millennium and the 21st century, and the 2nd year of the 2020s decade.

Like the year 2020, 2021 was also heavily defined by the COVID-19 pandemic, due to the emergence of multiple COVID-19 variants. The major global rollout of COVID-19 vaccines, which began at the end of 2020, continued in 2021. Most major events scheduled for 2020 that were postponed due to the pandemic were hosted in 2021, including the 26th United Nations Climate Change Conference, Expo 2020, and sporting events such as UEFA Euro 2020, the 2020 Summer Olympics and Paralympics, as well as the 2021 Copa América.

2021 additionally witnessed numerous advancements in space exploration, particularly by the United Arab Emirates, NASA and SpaceX, including the launch of the James Webb Space Telescope.

Civil unrest grew in 2021, with coups occurring in Sudan, Myanmar, Mali and Guinea, and insurrections occurring in Armenia and the United States.

Comfort (or being comfortable) is a sense of physical or psychological ease, often characterised as a lack of hardship. Persons who are lacking in comfort are uncomfortable, or experiencing discomfort. A degree of psychological comfort can be achieved by recreating experiences that are associated with pleasant memories, such as engaging in familiar activities, maintaining the presence of familiar objects, and consumption of comfort foods. Comfort is a particular concern in health care, as providing comfort to the sick and injured is one goal of healthcare, and can facilitate recovery. Persons who are surrounded with things that provide psychological comfort may be described as being "in their comfort zone". Because of the personal nature of positive associations, psychological comfort is highly subjective.

The use of "comfort" as a verb generally implies that the subject is in a state of pain, suffering or affliction, and requires alleviation from that state. Where the term is used to describe the support given to someone who has experienced a tragedy, the word is synonymous with consolation or solace. However, comfort is used much more broadly, as one can provide physical comfort to someone who is not in a position to be uncomfortable. For example, a person might sit in a chair without discomfort, but still find the addition of a pillow to the chair to increase their feeling of comfort. Something that provides this type of comfort, which does not seek to relieve hardship, can also be referred to as being "comfy".

A mattress is a large, usually rectangular pad for supporting a person lying down, especially for sleeping. It is designed to be used as a bed, or on a bed frame as part of a bed. Mattresses may consist of a quilted or similarly fastened case, usually of heavy cloth, containing materials such as hair, straw, cotton, foam rubber, or a framework of metal springs. Mattresses may also be filled with air or water.

Mattresses are usually placed on top of a bed base which may be solid, as in the case of a platform bed, or elastic, such as an upholstered wood and wire box spring or a slatted foundation. Popular in Europe, a divan incorporates both mattress and foundation in a single upholstered, footed unit. Divans have at least one innerspring layer as well as cushioning materials. They may be supplied with a secondary mattress or a removable "topper". Mattresses may also be filled with air or water, or a variety of natural fibers, such as in futons. Kapok is a common mattress material in Southeast Asia, and coir in South Asia.

Top most commonly refers to:

• Top, a basic term of orientation, distinguished from bottom, front, back, and sides
• Spinning top, a ubiquitous traditional toy
• Top (clothing), clothing designed to be worn over the torso
• Mountain top, a mountain peak located at some distance from the nearest point of higher elevation

Top may also refer to: