The army rank of captain (from the French capitaine) is a commissioned officer rank historically corresponding to command of a company of soldiers. The rank is also used by some air forces and marine forces. Today a captain is typically either the commander or second-in-command of a company or artillery battery (or United States Army cavalry troop or Commonwealth squadron). In the Chinese People's Liberation Army, a captain may also command a platoon, or be the second-in-command of a battalion.

In NATO countries the rank of captain is described by the code OF-2 and is one rank above an OF-1 (lieutenant or first lieutenant) and one below an OF-3 (major or commandant). The rank of captain is generally considered to be the highest rank a soldier can achieve while remaining in the field.

The rank of captain should not be confused with the naval rank of captain or with the Commonwealth Air Force rank of group captain, both of which are equivalent to the army rank of colonel.

Prior to the professionalization of the armed services of European nations subsequent to the French Revolution, a captain was a nobleman who purchased the right to head a company from the previous holder of that right. He would in turn receive money from another nobleman to serve as his lieutenant. The funding to provide for the troops came from the monarch or his government; the captain had to be responsible for it. If he was not, or was otherwise court-martialed, he would be dismissed ("cashiered"), and the monarch would receive money from another nobleman to command the company. Otherwise, the only pension for the captain was selling the right to another nobleman when he was ready to retire.

Captain America is a fictional character, a superhero who appears in comic books published by Marvel Comics. The character first appeared in Captain America Comics #1 (cover-dated March 1941), from Marvel Comics' 1940s predecessor, Timely Comics, and was created by Joe Simon and Jack Kirby. As of 2007, an estimated 210 million copies of "Captain America" comic books had been sold in 75 countries. For nearly all of the character's publication history, Captain America was the alter ego of Steve Rogers, a frail young man who was enhanced to the peak of human perfection by an experimental serum in order to aid the United States war effort. Captain America wears a costume that bears an American flag motif, and is armed with an indestructible shield that can be thrown as a weapon.

An intentionally patriotic creation who was often depicted fighting the Axis powers of World War II, Captain America was Timely Comics' most popular character during the wartime period. After the war ended, the character's popularity waned and he disappeared by the 1950s aside from an ill-fated revival in 1953. Captain America was reintroduced during the Silver Age of comics when he was revived from suspended animation by the superhero team the Avengers in The Avengers #4 (March 1964). Since then, Captain America has often led the team, as well as starring in his own series.

Karnal Sher Khan (1970–1999) (Urdu: کرنل شیر خان) was a Pakistan Army officer and one of only 11 recipients of Pakistan's highest gallantry award, the Nishan-e-Haider. He was a Captain in the 12 Northern Light Infantry (NLI) and, previously in 27 Sindh Regiment of the Pakistan.

Captain Sher Khan was born in Nawan Killi, a village in Swabi District of Khyber-Pakhtunkhwa. Karnal is localised form of Colonel. Karnel Sher Khan's home village of Nawan Kali (means: New Village) has now been named after him as Karnal Sher Killi (Village of Karnal Sher Khan).

Captain Sher Khan was the youngest of his two brothers and two sisters. His mother died in 1978 when he was eight. He was brought up by his paternal aunts. His family is deeply religious and they say that Sher was an embodiment of piety and Islamic teaching.

After completing his intermediate from Government College Swabi he joined Pakistan Air Force as an air man. On completion of his training, he was appointed electric fitter (aeronautical) at Risalpur. During these years he applied twice for commission in the Pakistan Army as a Commissioned Officer, as this was what he really wanted to do – he succeeded the second time. He joined the Pakistan Military Academy, Kakul in November 1992 and graduated in the 90th Long Course in 1994. His first posting was at Okara in 27th Sindh Regiment. Always smiling as a devoted soldier, he was fondly called Shera (Lion) and was very popular among his officers and colleagues. In January 1998 he volunteered to serve at the LoC in Kashmir, he was posted in 12 NLI.