From Longman Dictionary of Contemporary Englishlove letterˈlove letter noun [countable] TCMa letter that someone writes to tell someone else how much they love them
Examples from the Corpus
love letter• Leonardo forges a love letter from Emilia, and bribes a servant to deliver it to Eustathius along with Emilia's stolen glove.• With it was a love letter from another admirer.• It was a love letter, it was what she wanted and would she have the nerve to deliver it?• In the glove compartment of his car was another love letter, this time written by her husband.• I must have been about fifteen when I received my first love letter. 