What is "nat"

Nat \Nat\ (n[aum]t), adv. Not. [Obs.]
--Chaucer.

Nat \Nat\ [For ne at.] Not at; nor at. [Obs.]
--haucer.

Etymology 1 n. A spirit in Burmese mythology, whose cult is followed alongside Buddhism. Etymology 2

adv. (context obsolete English) not. (14th-17th c.) Etymology 3

n. logarithmic unit of information or entropy, based on natural logarithms

The nats (; ) are spirits worshipped in Burma (or Myanmar) in conjunction with Buddhism. They are divided between the 37 Great Nats and all the rest (i.e., spirits of trees, water, etc.). Almost all of the 37 Great Nats were human beings who met violent deaths (, lit. "green death"). They may thus also be called nat sein (; lit. green spirits). The word 'sein', while meaning 'green', is being used to mean 'raw' in this context. There are however two types of nats in Burmese Buddhist belief.

Nat spirits are termed lower nats or auk nats , whether named or unnamed, whereas ahtet nats or higher nat dewas inhabit the six heavens. Much like sainthood, nats can be designated for a variety of reasons, including those only known in certain regions in Burma. Nat worship is less common in urban areas than in rural areas, and is practised among ethnic minorities as well as in the mainstream Bamar society. It is however among the Buddhist Bamar that the most highly developed form of ceremony and ritual is seen.

Every Burmese village has a nat sin which essentially serves as a shrine to the village guardian nat called the ywa saung nat . An offertory coconut is often hung on the main southeast post in the house, wearing a gaung baung (headdress) and surrounded by perfume, as an offering to the Min Mahagiri (Lord of the Great Mountain), also known as the ein dwin or ein saung (house guardian) nat. One may inherit a certain member or in some instances two of the 37 Nats as mi hsaing hpa hsaing (; lit. mother's side, father's side) from one or both parents' side to worship depending on where their families originally come from. One also has a personal guardian spirit called ko saung nat .

The natural unit of information (symbol nat), sometimes also '''nit ''' or nepit, is a unit of information or entropy, based on natural logarithms and powers of e, rather than the powers of 2 and base 2 logarithms, which define the bit. This unit is also known by its unit symbol, the nat. The nat is the natural unit for information entropy. Physical systems of natural units that normalize Boltzmann's constant to 1 are effectively measuring thermodynamic entropy in nats.

When the Shannon entropy is written using a natural logarithm,

H =  − ∑plnp  

it is implicitly giving a number measured in nats.

One nat is equal to shannons (or bits) ≈ 1.44 Sh or, equivalently, hartleys ≈ 0.434 Hart. The factors 1.44 and 0.434 arise from the relationships

$$\left (2^x=e^1\Rightarrow x=\tfrac{1}{\ln 2}\right )$$
, and

$$\left (10^x=e^1\Rightarrow x=\tfrac{1}{\ln 10}\right )$$
. One nat is the information content of an event if the probability of that event occurring is 1/ e.

' Nat' is a given name or nickname, usually masculine, and also a surname.

Nat or NAT may also refer to:

The Nat are a Muslim community found in North India. A few are also found in the Terai region of Nepal. They are Muslim converts from the Hindu Nat caste.

Nat is a given name (usually masculine), nickname and surname.

It frequently is a nickname for Nathan, Nathaniel, Natalie, or Natalia.

It may refer to the following people: