a <xref>geometric</xref> <xref>drawing</xref> <xref>toy</xref> consisting of a <xref>set</xref> of <xref>plastic</xref> <xref>gears</xref> and <xref>toothed</xref> <xref>rings</xref>
User Defined Definitions
"a measuring instrument for recording the depth and rapidity of breathing movements"