Real Dictionary

valentine
countable noun: A valentine or a valentine card is a greetings card that you send to someone who you are in love with or are attracted to, usually without signing your name, on St Valentine's Day, the 14th of February.

valentine in American English
a sweetheart chosen or greeted on Saint Valentine's Day
noun: a card or message, usually amatory or sentimental but sometimes satirical or comical, or a token or gift sent by one person to another on Valentine Day, sometimes anonymously
noun: a male given name: from a Latin word meaning “ strong”

Valentine in American English 1
a masculine name

Valentine in American English 2
Saint(3 d cent. a.d.); Christian martyr of Rome: his day is Feb. 14

valentine in British English
noun: a card or gift expressing love or affection, sent, often anonymously, to one's sweetheart or satirically to a friend, on Saint Valentine's Day
noun: Saint. 3rd century ad, Christian martyr, associated by historical accident with the custom of sending valentines; bishop of Terni. Feast day: Feb 14