Prince consort
A prince consort, generally speaking, is the husband of a Queen regnant, unless he himself is a king.
Current examples include the Prince Philip, Duke of Edinburgh (husband of Queen Elizabeth II of the United Kingdom), and Prince Henrik of Denmark (husband of Queen Margrethe II of Denmark).
In recognition of his status, the prince consort can be given a formal title, such as Prince, Prince Consort (see below) or King Consort, with Prince being the most common. However, most monarchies do not have formal rules on the styling of princes consort, so it is quite feasible that such a person may be left entirely without royal titles. It is also not fully clear what would happen to the prince consort's title in the event that he were to outlive his wife, as this seems to have rarely occurred in the recorded annals of monarchy.
Prince Consort (capitalized) is quite different from the above as it is a formal title. Prince Albert of Saxe-Coburg and Gotha is the only British prince consort to have ever held it. It was awarded to him in 1857 by his wife, Queen Victoria (reigned 1837-1901).
The female counterpart of the title, Princess Consort, has also never been used in Western monarchies, as wives of Kings have usually always been Queens. However, it has been said that when the present Prince of Wales becomes the sovereign, his wife will not be known as The Queen but rather as The Princess Consort (see Duchess of Cornwall and Princess Consort). An example of the title of Princess Consort being used is Princess Lalla Salma of Morocco.