A type of imperfect rhyme where only part of the words rhyme with each other. The term comes from the word apocope, which just means to cut off a syllable (i.e., morn instead of morning). To work well, stressed syllables should be rhymed together.
feel/really
come/summer
wordless/bird
Usually the penultimate syllable of one line is rhymed with an end rhyme:
Blah blah-diddy blah
cope
Etc poop poop diggity
hopeless
But this is the norm, not the rule. Ira Gershwin's song Happy Ending has an example of an internal apocopated rhyme:
Though we
feel
Our lot is terrible,
It is
really not unbearable;
Though I've seen that last line transcribed as:
It is real
ly not unbearable;
Which is really unbearable.