Title: 180th meridian
Content: the Gilbert Islands and the Phoenix Islands of Kiribati ; North Island and the Kermadec Islands of New Zealand ; the Bounty Islands and the Chatham Islands, also of New Zealand  The 180th meridian or antimeridian is the meridian 180° both east and west of the Prime Meridian, with which it forms a great circle dividing the earth into the Western and Eastern Hemispheres. It is common to both east longitude and west longitude. It mostly passes through the open waters of the Pacific Ocean, but passes across land in Russia, Fiji, and Antarctica. This meridian is used as the basis for the International Date Line, but the latter deviates from it to maintain date consistency within the territories of Russia, the United States, Kiribati, Fiji and New Zealand. Starting at the North Pole and heading south to the South Pole, the 180th meridian passes through: The meridian also passes between (but not particularly close to): The only place where roads cross this meridian, and where there are buildings very close to it, is in Fiji.
Title: 80th meridian east
Content:  The meridian 80° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole. The 80th meridian east forms a great circle with the 100th meridian west. There is also an 80 Degrees East cafe in Nanganallur, Chennai, India named after this longitude.
Title: Longitude
Content:   Longitude (, AU and UK also ) is a geographic coordinate that specifies the east–west position of a point on the Earth's surface, or the surface of a celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians (lines running from pole to pole) connect points with the same longitude. The prime meridian, which passes near the Royal Observatory, Greenwich, England, is defined as 0° longitude by convention. Positive longitudes are east of the prime meridian, and negative ones are west. Because of the Earth's rotation, there is a close connection between longitude and time. Local time (for example from the position of the Sun) varies with longitude: a difference of 15° longitude corresponds to a one-hour difference 
Title: 18th parallel south
Content:  The 18th parallel south is a circle of latitude that is 18 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America.
Title: 88th meridian east
Content:  The meridian 88° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole. The 88th meridian east forms a great circle with the 92nd meridian west.
Title: Meridian (geography)
Content:   In geography and geodesy, a meridian (or line of longitude) is the half of an imaginary polar great circle or great ellipse on the Earth's surface, a coordinate line terminated by the North Pole and the South Pole. A meridian is the locus connecting points of equal longitude, which is the angle (in degrees or other units) east or west of a given prime meridian (currently, the IERS Reference Meridian). The position of a point along the meridian is given by that longitude and its latitude, measured in angular degrees north or south of the Equator. Each meridian is perpendicular to all circles of latitude. Meridians are half of a great circle on the Earth's surface. The length of a meridian on a modern ellipsoid model of the earth (WGS 84) has been estimated at 20,003.93 km (12,429.9 miles).
Title: Longitude
Content:  Longitude is given as an angular measurement ranging from 0° at the Prime Meridian to +180° eastward and −180° westward. The Greek letter λ (lambda) is used to denote the location of a place on Earth east or west of the Prime Meridian. Each degree of longitude is sub-divided into 60 minutes, each of which is divided into 60 seconds. A longitude is thus specified in sexagesimal notation as, for example, 23° 27′ 30″ E. For higher precision, the seconds are specified with a decimal fraction. An alternative representation uses degrees and minutes, and parts of a minute are expressed in decimal notation, thus: 23° 27.5′ E. Degrees may also be expressed as a decimal fraction: 
Title: 158th meridian east
Content:  The meridian 158° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Pacific Ocean, Australasia, the Southern Ocean, and Antarctica to the South Pole. The 158th meridian east forms a great circle with the 22nd meridian west.
Title: International Date Line
Content: This description is based on the most common understanding of the de facto International Date Line. See below, and map above at right. The IDL is roughly based on the meridian of 180° longitude, roughly down the middle of the Pacific Ocean, and halfway around the world from the IERS Reference Meridian. In many places, the IDL follows the 180° meridian exactly. In other places, however, the IDL deviates east or west away from that meridian. These various deviations generally accommodate the political and/or economic affiliations of the affected areas. Proceeding from north to south, the first deviation of the IDL from 180° is to 
Title: 120th meridian east
Content:  The meridian 120° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, Australia, the Southern Ocean, and Antarctica to the South Pole. In mean solar time this offset is the UTC+08:00 time zone. The 120th meridian east forms a great circle with the 60th meridian west.

Question: what is the 180 degree line of longitude called?
Answer: 180th meridian or antimeridian.
180th meridian.
antimeridian.