A lexical relation which concerns two or more distinct words that happen to share the same form in sound (homophones) and/or in writing (homographs).

For example, the form bank relates to two different words with unrelated meanings, 'financial institution' and 'side of a river'. These two senses are not only synchronically unrelated (unrelated in current usage) but also historically unrelated. The word bank with the meaning 'side of a river' has been in the English language for much longer, and is related to the Old Icelandic word for 'hill', while the word bank meaning 'financial institution' was borrowed from the Italian banca, meaning 'money changer's table'.