I'm just guessing that maybe you are referring to a male name Kaz, or Kazu, which is normally an abbreviated version (nickname) of longer names such as Kazuo, Kazuhiro, Kazuhiko, Kazutoshi, etc., etc., there are many male names that start with kazu-.
Definition of Quatrain. A quatrain is a verse with four lines, or even a full poem containing four lines, having an independent and separate theme. Often one line consists of alternating rhyme, existing in a variety of forms.
Definition of Couplet. A couplet is a literary device which can be defined as having two successive rhyming lines in a verse and has the same meter to form a complete thought. It is marked by a usual rhythm, rhyme scheme and incorporation of specific utterances.