The Royal Order of the Seraphim (Swedish Kungliga Serafimerorden) (Seraphim being a category of Angels) is a Swedish Royal order of chivalry created by King Frederick I of Sweden on 23 February 1748, together with the Order of the Sword and the Order of the Polar Star. After the reorganization of the orders in 1975 the order is only awarded to foreign heads of state and members of the royal family (the last non-royal Swedish holder was Sten Rudholm). The order has only one class with the dignity of Knight (Member for women and Member of the Cloth for clergymen), and is the foremost order of Sweden.

The three above mentioned Orders together with the Order of Vasa form the Orders of His Majesty the King (Swedish Kungl. Maj:ts Orden), a term also used for the chancellery of the Orders in the Royal Palace. A Swedish Knight (Member/of the Cloth) of the Order of the Seraphim is not referred to as a Knight (Member/of the Cloth) of the Seraphim, but rather as a Knight and Commander of the Orders of His Majesty the King (Swedish: Riddare och Kommendör av Kunglig Majestäts Orden). This form is used because the Swedish word orden is an old plural form which indicates that a knight has to be a Commander Grand Cross or 1st Class of at least one of the other Swedish Orders. Foreign Knights are for the greater part Knights of the Order of the Seraphim. A Knight of the Order may be styled "Herr" + surname, which used to be the formal style for Swedish secular Knights (untitled high-ranking noblemen) appointed by the Swedish King, a practice that ceased in the 17th Century. Until 1975 the sons of the Swedish monarch were borne knights of the Order. At present the sons and daughters of the Swedish monarch do not become knights and members of the Order until they are eighteen years of age.

A seraph (pl. seraphim ( /ˈsɛr.ə.fɪm/); Hebrew: שְׂרָפִים śərāfîm, singular שָׂרָף śārāf; Latin: seraphi[m], singular seraph[us]; Greek: σεραφείμ) is a type of celestial or heavenly being in the Abrahamic religions.

Literally "burning ones", the word seraph is normally a synonym for serpents when used in the Hebrew Bible. A seminal passage in the Book of Isaiah (6.1-8) used the term to describe fiery six-winged beings that fly around God's throne singing "holy, holy, holy". This throne scene, with its triple invocation of holiness (a formula that came to be known as the trisagion), profoundly influenced subsequent theology, literature and art. Its influence is frequently seen in works depicting angels, heaven and apotheosis. Seraphs are mentioned as celestial beings in an influential Hellenistic work, the Book of Enoch, and the Book of Revelation. Tradition places seraphs in the fifth rank of ten in the Jewish angelic hierarchy and the highest rank in the Christian angelic hierarchy.

The word seraphim, literally "burning ones", transliterates a Hebrew plural noun; translation yields seraphs. The singular, "seraph", is more properly rendered sarap. The word sarap/seraphim appears three times in the Torah (Numbers 21:6-8, Deuteronomy 8:15) and four times in the Book of Isaiah (6:2-6, 14:29, 30:6). In Numbers and Deuteronomy the "seraphim" are serpents – the association of serpents as "burning ones" is possibly due to the burning sensation of the poison. Isaiah also uses the word in close association with words to describe snakes (nahash, the generic word for snakes, in 14:29, and efeh, viper, in 30:6).

In mathematics, big O notation is used to describe the limiting behavior of a function when the argument tends towards a particular value or infinity, usually in terms of simpler functions. It is a member of a larger family of notations that is called Landau notation, Bachmann–Landau notation (after Edmund Landau and Paul Bachmann), or asymptotic notation. In computer science, big O notation is used to classify algorithms by how they respond (e.g., in their processing time or working space requirements) to changes in input size.

Big O notation characterizes functions according to their growth rates: different functions with the same growth rate may be represented using the same O notation. A description of a function in terms of big O notation usually only provides an upper bound on the growth rate of the function. Associated with big O notation are several related notations, using the symbols o, Ω, ω, and Θ, to describe other kinds of bounds on asymptotic growth rates.

Big O notation is also used in many other fields to provide similar estimates.

Annie Mac (born Annie MacManus; 18 July 1978 in Dublin) is an Irish DJ and television presenter who hosts an eponymous electronic dance music show on BBC Radio 1 in the United Kingdom which airs at 7:00 pm on Friday evenings as well as a Sunday evening show alongside co-presenter Nick Grimshaw.

Annie Mac was born in Dublin, Ireland. She studied English Literature at Queens University, in Belfast, Northern Ireland. Annie lives in London with her boyfriend, fellow club and Radio 1 DJ, Toddla T. Her brother, Davey McManus, was the lead singer and guitarist in The Crocketts.

Annie currently hosts a number of shows on Radio 1. Her main show, Annie Mac's Mash Up, airs 7:00 pm to 9:00 pm on Friday nights. She also hosted BBC Switch with Nick Grimshaw on Sunday evenings from 7:00 pm to 10:00 pm until 21 March 2010. After this date they moved to 10:00pm - midnight with a new show simply called Nick Grimshaw and Annie Mac. She is currently one of only two presenters on the station to present shows in both the specialist and entertainment sector, the other being Huw Stephens.