Why is it called a 'feminine rhyme'?

Solution 1:

The names come from French, where (from French Wikipédia)

A rhyme is called feminine when the last phoneme is a mute e (formerly called an "e féminin").

That is, a rhyme was called feminine if the words ended with a mute e. Back when the rules for French poetry were formulated, these e's were pronounced, but unstressed, and one name for them was feminine e's. Mute e's are still pronounced when reading poetry and when singing, although not in normal speech.

Why were they called feminine e's? It probably didn't have anything to do with mute e's being weaker or more girly-sounding in any sense; they were called feminine e's because, to turn male adjectives and some male nouns into female ones, you added a mute e. For example, in French, a big black cat is:

un gros chat noir (boy cat),
une grosse chatte noire (girl cat).

This rule in French applies only for adjectives and some nouns which have male/female versions (e.g., chanteur, chanteuse); there are quite a few masculine nouns that end in mute e's and feminine nouns that don't.

You can see that the name "feminine rhyme" originated in French by looking at the reference (from London, 1764) T Romano gives in his answer, where a feminine rhyme is defined as one ending in an e-mute. In English, words (e.g., state and gait) rhyme whether or not they end in a silent e.

Solution 2:

According to volume 4 of A New and Complete Dictionary of Arts and Sciences: Comprehending All the Branches of Useful Knowledge, with Accurate Descriptions as Well of the Various Machines, Instruments, Tools, Figures, and Schemes Necessary for Illustrating Them, as of the Classes, Kinds, Preparations, and Uses of Natural Productions, Whether Animals, Vegetables, Minerals, Fossils, Or Fluids; Together with the Kingdoms, Provinces, Cities, Towns, and Other Remarkable Places Throughout the World (London, 1764),

a feminine rhyme is that where the last syllable of the rhyme ends with an e-mute

The passage goes on to say:

There is no rule in poetry...whose observance costs so much trouble, and is productive of less beauties in verse, than that of rhyming...

Solution 3:

According To the following source it comes from the French language distinction of words according to gender and the 'weak' rhymes that unaccented syllables suggest.

• According to one source in the English Department at Carson-Newman College, (http://web.cn.edu/kwheeler/lit_terms_R.html) the word "rhyme" itself originates "from Old French, rime meaning 'series,' in turn adopted from Latin 'rithmus' and Greek 'rhythmos'." Given some of the other gender assignments in Greek and Latin, might we ascribe gender features to the rhyming verses penned by the early Greeks and Romans?

• No doubt, the definition of gender in rhyme could probably be argued until the cows come home, with a break taken only for milking before the debate starts again. As is true with virtually any sorting out of why words in any language might be classified as masculine versus feminine, rhymes are no different. *One thing seems clear: at least in English, gender in rhyme seems to have little or nothing to do with the gender rules found in some romance languages.

• That is, whether a line of verse in English ends in an "a" or "o" or other gender laden vowel or consonant, doesn't really matter as much as it does in the Spanish language. And speaking of word endings, despite its compromise value in the Italian language, the use of a neutral vowel (such as the letter "i") at the end of the plural form of both masculine and feminine words is not a gender-driven issue in English rhyme. But you have to admire the logical recognition of not being able to sort out gender in groups.

• In the French language, the definition suggests line ending words which end in "e" are feminine and those that don't are masculine. Some sources also refer to "e" endings and unaccented ending syllables as being weak.

(billkirkwrites.blogspot)