ICG Navik GD key terms

The angular distance of a place north or south of the equator, measured in degrees from 0 at the equator to 90 at the poles. It is used to fix position on the globe.

The angular distance of a place east or west of the prime meridian, measured in degrees from 0 to 180. Lines of longitude converge at the poles and help fix time and position.

An imaginary line circling the Earth exactly halfway between the North and South Poles, at 0 degrees latitude. It divides the planet into the Northern and Southern Hemispheres.

The imaginary line of 0 degrees longitude passing through Greenwich, England. It is the reference line for measuring east-west position and for standard time zones.

The line of latitude about 23.5 degrees north of the equator, the northernmost point where the Sun can appear directly overhead. It marks the boundary of the torrid zone.

A seasonal reversal of wind direction that brings heavy rainfall, most famously over South Asia. In India the southwest monsoon brings most of the annual rain between June and September.

A large low-pressure weather system with strong rotating winds around a centre. In the Bay of Bengal and Arabian Sea such storms can bring destructive wind and rain to coastal India.

The regular rise and fall of sea level caused mainly by the gravitational pull of the Moon and Sun. Tides are important for navigation, ports and coastal fishing.

A group or chain of islands lying close together in a sea or ocean. Examples include the Andaman and Nicobar Islands and the Lakshadweep group belonging to India.

A piece of land almost surrounded by water but still joined to the mainland. India is often described as a peninsula because the sea borders it on three sides.

A large part of an ocean or sea that extends into land, partly enclosed by coast. The Gulf of Kutch and the Gulf of Khambhat lie along India's western coast.

Basic freedoms guaranteed to citizens by Part III of the Indian Constitution, such as equality, speech and life. They can be enforced in court through writs.

Guidelines in Part IV of the Indian Constitution that direct the State towards social and economic welfare. They are not enforceable in court but are fundamental in governance.

The introductory statement of the Indian Constitution declaring the source of its authority and its aims of justice, liberty, equality and fraternity. It describes India as a sovereign socialist secular democratic republic.

The power of an authority to reject a decision or proposal and stop it from becoming law. In the United Nations Security Council, permanent members hold this power.

A comparison of two quantities of the same kind, showing how many times one contains the other. It is written with a colon, such as 3:4.

An equation stating that two ratios are equal, such as a:b = c:d. In a proportion the product of the extremes equals the product of the means.

A way of expressing a number as a fraction of one hundred. For example, 25 percent means 25 out of every 100, or one quarter of the whole.

The sum of a set of values divided by the number of values. Also called the arithmetic mean, it gives a single value representing the whole group.

The middle value in a set of numbers arranged in order. If there is an even count, it is the average of the two central values.

Interest calculated only on the original principal for the whole period, using the formula principal times rate times time divided by one hundred.

Interest calculated on the principal plus any interest already added, so the amount grows faster than with simple interest over the same period.

The distance covered by an object in unit time, usually written as distance divided by time. Common units are metres per second and kilometres per hour.

The highest common factor: the largest number that divides two or more given numbers exactly without leaving a remainder. It is used to simplify fractions.

The lowest common multiple: the smallest number that is a multiple of two or more given numbers. It helps in adding fractions with different denominators.

A push or pull that changes or tends to change the speed, direction or shape of an object. It is measured in newtons and has both magnitude and direction.

Three rules describing motion: objects stay at rest or in uniform motion unless a force acts; force equals mass times acceleration; and every action has an equal and opposite reaction.

The rate at which velocity changes with time, including speeding up, slowing down or changing direction. It is measured in metres per second squared.

The speed of an object in a stated direction. Because direction matters, a change of direction is a change of velocity even if speed stays the same.

The mass of a substance per unit volume, usually expressed in kilograms per cubic metre or grams per cubic centimetre. Objects less dense than water float on it.

The force acting perpendicular to a surface divided by the area of that surface. It is measured in pascals, and in fluids it increases with depth.

The upward force that a fluid exerts on a body placed in it, caused by pressure differences. It explains why ships and boats float on water.

The bending of light as it passes from one transparent medium into another of different density, such as from air into water. It makes objects appear shifted or bent.

The bouncing back of light when it strikes a surface. The angle of incidence equals the angle of reflection, which is why mirrors form images.

A curved piece of transparent material that bends light to form an image. Convex lenses converge light and concave lenses diverge it.

A word that names a person, place, thing or idea, such as sailor, harbour, anchor or courage. Nouns can be proper, common, collective or abstract.

A word used in place of a noun to avoid repetition, such as he, she, it, they or who. The noun it replaces is called its antecedent.

A word that describes or gives more information about a noun or pronoun, such as rough, deep or calm. It usually comes before the noun or after a linking verb.

A word that modifies a verb, an adjective or another adverb, often telling how, when or where. Many adverbs end in -ly, such as quickly or carefully.

A word that expresses an action, occurrence or state of being, such as sail, rise or is. Every complete sentence needs a verb.

The part of a sentence that names the person or thing performing the action or being described. It must agree with the verb in number and person.

The part of a sentence that says something about the subject, containing the verb and its objects or complements. Together with the subject it forms a complete sentence.

A word that has the same or nearly the same meaning as another word, such as begin and start. Synonyms help avoid repetition in writing.

A word that has the opposite meaning of another word, such as fast and slow. Antonyms are used to express contrast in speech and writing.