What is "niche"

Niche \Niche\ (n[i^]ch), n. [F., fr. It. nicchia, prop., a shell-like recess in a wall, fr. nicchio a shellfish, mussel, fr. L. mytilus.] A cavity, hollow, or recess, generally within the thickness of a wall, for a statue, bust, or other erect ornament. Hence, any similar position, literal or figurative.

Images defended from the injuries of the weather by niches of stone wherein they are placed.
--Evelun.

1610s, "shallow recess in a wall," from French niche "recess (for a dog), kennel" (14c.), perhaps from Italian nicchia "niche, nook," from nicchio "seashell," said by Klein and Barnhart to be probably from Latin mitulus "mussel," but the change of -m- to -n- is not explained. Watkins suggests that the word is from an Old French noun derived from nichier "to nestle, nest, build a nest," via Gallo-Roman *nidicare from Latin nidus "nest;" but that has difficulties, too. Figurative sense is first recorded 1725. Biological use dates from 1927.

n. 1 (context architecture English) A cavity, hollow, or recess, generally within the thickness of a wall, for a statue, bust, or other erect ornament. Hence, any similar position, literal or figurative. 2 (context biology English) A function within an ecological system to which an organism is especially suited. 3 (context by extension English) Any position of opportunity for which one is well-suited, such as a particular market in business. 4 An arrow woven into a Muslim prayer rug pointing in the direction of Mecc

1. v

2. (context transitive marketing English) To specialize in a niche, or particular narrow section of the market.

1. n. a position particularly well suited to the person who occupies it; "he found his niche in the academic world"

2. a small concavity [syn: recess, recession, corner]

3. an enclosure that is set back or indented [syn: recess]

4. (ecology) the status of an organism within its environment and community (affecting its survival as a species) [syn: ecological niche]

A niche ( CanE, or ) in classical architecture is an exedra or an apse that has been reduced in size, retaining the half-dome heading usual for an apse. Nero's Domus Aurea (AD 64–69) was the first semi-private dwelling that possessed rooms that were given richly varied floor plans, shaped with niches and exedras; sheathed in dazzling polished white marble, such curved surfaces concentrated or dispersed the daylight.

The word derives from the Latin nidus or nest, via the French niche. The Italian nicchio for a sea-shell may also be involved, as the traditional decoration for the top of a niche is a scallop shell, as in the illustration, hence also the alternative term of "conch" for a semi-dome, usually reserved for larger exedra.

In Gothic architecture, a niche may be set within a tabernacle framing, like a richly-decorated miniature house (" aedicule"), such as might serve for a reliquary. The backings for the altars in churches (" reredos") can be embedded with niches for statues. Though a niche in either Classical or Gothic contexts may be empty and merely provide some articulation and variety to a section of wall, the cult origins of the niche suggested that it be filled with a statue. One of the earliest buildings which uses external niches containing statues is the Church of Orsanmichele in Florence, built between 1380-1404. The Uffizi Palace in Florence (1560–81) modified the concept by setting the niche within the wall so it did not protrude. The Uffizi has two dozen or so such niches containing statues of great historical figures. In England the Uffizi style niches were adopted at Montacute House (c. 1598), where there are 9 exterior niches containing statues of the Nine Worthies. In Fra Filippo Lippi's Madonna (illustration, right) the trompe-l'oeil niche frames her as with the canopy of estate that was positioned over a personage of importance in the late Middle Ages and Early Modern Europe. At the same time, the Madonna is represented as an iconic sculpture who has "come alive" with miraculous immediacy.

Expanding from its primary sense as an architectural recess, a niche can be applied to a rocky hollow, crack, crevice, or foothold. The sense of a niche as a clearly defined narrow space led to its use describing the relational position of an organism's species, its ecological niche.

Niche.com, Inc., formerly known as College Prowler, is an American company headquartered in Pittsburgh, Pennsylvania, that runs a ranking and review site. The company was founded by Luke Skurman in 2002 as a publisher of print guidebooks on US colleges, but now runs a website with information on K-12 schools, colleges, cities, and neighborhoods.

Niche (foaled 1990) is a British Thoroughbred racehorse best known for winning the Group 3 classic trial the Nell Gwyn Stakes and coming 2nd in the 1,000 Guineas, before her career was cut short by a freak accident on the gallops.

Bred by Highclere Stud, Niche was owned by Lord Carnarvon - the Queen's racing manager, owner of top class fillies Lemon Souffle and Lyric Fantasy, and grandson of George Edward Stanhope Molyneux Herbert, 5th Earl of Carnarvon who discovered the tomb of Tutenkhamun.

Niche ( or ) may refer to:

• Niche (architecture), an exedra or an apse that has been reduced in size
  • A cell of a columbarium for a cremation urn
• Niche (company), an Internet search and review service
• Niche (horse), a British Thoroughbred racehorse
• Stem cell niche, the necessary cellular environment of a stem cell
• Niche (protein structural motif)
• Bassline (dance music), a type of music related to UK garage also called niche
• Developmental niche, a concept for understanding the cultural context of child development
• Ecological niche, a term describing the relational position of an organism's species
• Niche market, a focused, targetable portion (subset) of a market sector
  • Niche blogging, a blog focused on a niche market (above)

In the area of protein structural motifs, niches are three or four amino acid residue features in which main-chain CO groups are bridged by positively charged or δ+ groups. The δ+ groups include groups with two hydrogen bond donor atoms such as NH groups and water molecules. In typical proteins, 7% of amino acid residues belong to niches bound to a δ+ group, while another 7% have the conformation but no single cationic bridging group is detected. Two websites are available for examining niches in proteins, Motivated Proteins: 1; or PDBeMotif: 2.

Niches are of two kinds, distinguished as niche3 (3 residues, i to i+2) and niche4 (4 residues, i to i+3). In a niche3 motif the δ+-binding carbonyl group is from residues i and i+2 while in a niche4 motif it is from residues i and i+3.

A niche3 has the α conformation for residue i+1 and the β conformation for residue i+2; a niche4 has the α conformation for residues i+1 and i+2 and the β conformation for residue i+3.

A niche occurs commonly at the C-terminus of α-helices especially of 3 helices.

Metal ions that occur bound to niches in proteins are Na+, K+, Ca++ and Mg++. Proteins with regulatory cations often employ niches for metal binding ( thrombin, Na+; annexin, Ca++; pyruvate dehydrogenase, K+).

A major cation transporter in cells is calcium ATPase. In the Ca++-bound crystal structures the two calcium ions side-by-side within the transmembrane domain are thought to be at the halfway stage of being transported. As well as being bound by various side chain carbonyl groups, one of these calcium ions is bound by a niche3/niche4 (both in the one motif) at residues 304–307 at the C-terminus of an α-helix.

Another small tripeptide motif that binds cations or δ+ groups via main-chain CO groups is called the catgrip.