Measuring instrument for measuring the luminous intensity of a source by comparing it (visually or photoelectrically) with a standard source; photographic equipment that measures the intensity of light.

intellectual and practical activity encompassing systematic study of structure and behaviour of physical and natural world.

celestial body moving round star. One of the bodies that orbit the sun.

find unexpectedly or while searching.

set boat in motion.

shape formed by two intersecting lines. Animals/plants resulting from combining two breeds. To put one thing over another e.g. arms.

continuing or valid to final destination. expressing movement into one side and out of other side of opening etc.. Over, in, across an entire thing or place.

Tube-shaped device used to see a great distance. slide or cause to slide into itself, so that it becomes smaller.

something twice as large as usual. Two teams of two people playing tennis. To be used for two functions at the same time.

In particular.

Biggest.

distant in space or time.

Being what was wanted or needed. used to greet someone in polite or friendly way. Friendly greeting to someone who has arrived. To accept or receive something happily and gladly.