OXFORD DICTIONARY
leonine, adj. & n.
--adj. of Pope Leo; made or invented by Pope Leo.
--n. (in pl.) leonine verse.
Leonine City the part of Rome round the Vatican fortified by Pope Leo IV. leonine verse 1 medieval Latin verse in hexameter or elegiac metre with internal rhyme.
2 English verse with internal rhyme.
the name Leo (as LEONINE)
leonine, adj.
1 like a lion.
2 of or relating to lions.
ME f. OF leonin -ine or L leoninus f. leo leonis lion
DEVIL DICTIONARY
leonine
adj. Unlike a menagerie lion. Leonine verses are those in
which a word in the middle of a line rhymes with a word at the end, as
in this famous passage from Bella Peeler Silcox:
The electric light invades the dunnest deep of Hades.
Cries Pluto, 'twixt his snores: "O tempora! O mores!"
It should be explained that Mrs. Silcox does not undertake to
teach pronunciation of the Greek and Latin tongues. Leonine verses
are so called in honor of a poet named Leo, whom prosodists appear to
find a pleasure in believing to have been the first to discover that a
rhyming couplet could be run into a single line.