A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean , a lake , or another bay. A large bay is usually called a gulf , sea , sound , or bight . A cove is a small, circular bay with a narrow entrance. A fjord is an elongated bay formed by glacial action. The term embayment is also used for related features , such as extinct bays or freshwater environments.
20-538: Liverpool Bay is a bay of the Irish Sea between northeast Wales , Cheshire , Lancashire and Merseyside to the east of the Irish Sea. The bay is a classic example of a region of freshwater influence. Liverpool Bay has historically suffered from reduced oxygen content from prior massive discharges of sewage sludge, according to C. Michael Hogan. The rivers Alt , Clwyd , Dee , Ribble and Mersey drain into
40-538: A code point in Unicode at U+2300 ⌀ DIAMETER SIGN , in the Miscellaneous Technical set. It should not be confused with several other characters (such as U+00D8 Ø LATIN CAPITAL LETTER O WITH STROKE or U+2205 ∅ EMPTY SET ) that resemble it but have unrelated meanings. It has the compose sequence Compose d i . The diameter of
60-461: A curve of constant width such as the Reuleaux triangle , the width and diameter are the same because all such pairs of parallel tangent lines have the same distance. For an ellipse , the standard terminology is different. A diameter of an ellipse is any chord passing through the centre of the ellipse. For example, conjugate diameters have the property that a tangent line to the ellipse at
80-425: A more general definition that is valid for any kind of n {\displaystyle n} -dimensional (convex or non-convex) object, such as a hypercube or a set of scattered points. The diameter or metric diameter of a subset of a metric space is the least upper bound of the set of all distances between pairs of points in the subset. Explicitly, if S {\displaystyle S}
100-499: A variety of shoreline characteristics as other shorelines. In some cases, bays have beaches , which "are usually characterized by a steep upper foreshore with a broad, flat fronting terrace". Bays were significant in the history of human settlement because they provided easy access to marine resources like fisheries . Later they were important in the development of sea trade as the safe anchorage they provide encouraged their selection as ports . The United Nations Convention on
120-706: Is not recognised by the British Government as a strategic economic sub-region, however. Despite having its advocates, the term is still not particularly common in the area. The English portion of the Liverpool Bay land area is one of the 120 natural areas into which England is divided by Natural England for nature conservation purposes. Wind turbines which are the biggest in the world as of 2017 have been installed in Liverpool Bay. 53°32′N 3°12′W / 53.533°N 3.200°W / 53.533; -3.200 Bay A bay can be
140-578: Is occasionally referred to as the "Liverpool Bay Area". Though the term is seen by some as a possible official alternative to Merseyside, it is more often used to describe a much wider area which may include the West Lancashire towns of Ormskirk and Skelmersdale to the north, St Helens and Warrington to the east and Chester plus North Wales to the south. In this sense, it is often promoted by local thinkers and urbanists to encourage regional co-operation in both economic and cultural terms. It
160-446: Is the same as the diameter of its convex hull . In medical terminology concerning a lesion or in geology concerning a rock, the diameter of an object is the least upper bound of the set of all distances between pairs of points in the object. In differential geometry , the diameter is an important global Riemannian invariant . In planar geometry , a diameter of a conic section is typically defined as any chord which passes through
180-453: Is the subset and if ρ {\displaystyle \rho } is the metric , the diameter is diam ( S ) = sup x , y ∈ S ρ ( x , y ) . {\displaystyle \operatorname {diam} (S)=\sup _{x,y\in S}\rho (x,y).} If the metric ρ {\displaystyle \rho }
200-448: Is the world's largest bay. Bays also form through coastal erosion by rivers and glaciers . A bay formed by a glacier is a fjord . Rias are created by rivers and are characterised by more gradual slopes. Deposits of softer rocks erode more rapidly, forming bays, while harder rocks erode less quickly, leaving headlands . Diameter In geometry , a diameter of a circle is any straight line segment that passes through
220-400: Is viewed here as having codomain R {\displaystyle \mathbb {R} } (the set of all real numbers ), this implies that the diameter of the empty set (the case S = ∅ {\displaystyle S=\varnothing } ) equals − ∞ {\displaystyle -\infty } ( negative infinity ). Some authors prefer to treat
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#1732773297796240-478: The conic's centre ; such diameters are not necessarily of uniform length, except in the case of the circle, which has eccentricity e = 0. {\displaystyle e=0.} The symbol or variable for diameter, ⌀ , is sometimes used in technical drawings or specifications as a prefix or suffix for a number (e.g. "⌀ 55 mm"), indicating that it represents diameter. Photographic filter thread sizes are often denoted in this way. The symbol has
260-594: The estuary of a river, such as the Chesapeake Bay , an estuary of the Susquehanna River . Bays may also be nested within each other; for example, James Bay is an arm of Hudson Bay in northeastern Canada . Some large bays, such as the Bay of Bengal and Hudson Bay, have varied marine geology . The land surrounding a bay often reduces the strength of winds and blocks waves . Bays may have as wide
280-503: The Law of the Sea defines a bay as a well-marked indentation in the coastline, whose penetration is in such proportion to the width of its mouth as to contain land-locked waters and constitute more than a mere curvature of the coast. An indentation, however, shall not be regarded as a bay unless its area is as large as (or larger than) that of the semi-circle whose diameter is a line drawn across
300-524: The bay. The bay is littered with wrecks and has many dive sites . The bay also contains several oil and gas fields including the Douglas Complex , with a combined daily capacity (January 2008) of 60,000 barrels . The UK's first major offshore wind farm, North Hoyle , is located in the south of the bay, which is a busy shipping route to the Mersey Docks . The land area around the bay
320-401: The centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere . In more modern usage, the length d {\displaystyle d} of a diameter is also called the diameter. In this sense one speaks of the diameter rather than a diameter (which refers to
340-414: The empty set as a special case, assigning it a diameter of 0 , {\displaystyle 0,} which corresponds to taking the codomain of ρ {\displaystyle \rho } to be the set of nonnegative reals. For any solid object or set of scattered points in n {\displaystyle n} -dimensional Euclidean space , the diameter of the object or set
360-636: The endpoint of one diameter is parallel to the conjugate diameter. The longest diameter is called the major axis . The word "diameter" is derived from Ancient Greek : διάμετρος ( diametros ), "diameter of a circle", from διά ( dia ), "across, through" and μέτρον ( metron ), "measure". It is often abbreviated DIA , dia , d , {\displaystyle {\text{DIA}},{\text{dia}},d,} or ∅ . {\displaystyle \varnothing .} The definitions given above are only valid for circles, spheres and convex shapes. However, they are special cases of
380-494: The line segment itself), because all diameters of a circle or sphere have the same length, this being twice the radius r . {\displaystyle r.} For a convex shape in the plane , the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the width is often defined to be the smallest such distance. Both quantities can be calculated efficiently using rotating calipers . For
400-458: The mouth of that indentation — otherwise it would be referred to as a bight . There are various ways in which bays can form. The largest bays have developed through plate tectonics . As the super-continent Pangaea broke up along curved and indented fault lines, the continents moved apart and left large bays; these include the Gulf of Guinea , the Gulf of Mexico , and the Bay of Bengal , which
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