A searchlight's an apparatus with reflectors for projecting a powerful beam of light of approximately parallel rays in a particular direction, usually devised so that it can be swiveled about. Military use of searchlights started late 19th century, when battleships and other major vessels were equipped for finding small attacking torpedoboats. They saw use in the Russo-Japanese War 1904 - 05. Searchlights were also installed on many coastal artillery batteries for aiding night combat. In World… (More on Searchlight)