PIPERONAL
Pip`er*o"nal, n. (Chem.)

Defn: A white crystalline substance obtained by oxidation of piperic acid, and regarded as a complex aldehyde.

PIPERYLENE
Pi*per"y*lene, n. Etym: [Piperidine + acetylene.] (Chem.)

Defn: A hydrocarbon obtained by decomposition of certain piperidine derivatives.

PIPESTEM
Pipe"stem`, n.

Defn: The hollow stem or tube of a pipe used for smoking tobacco,
etc.
Took a long reed for a pipestem. Longfellow.

PIPESTONE
Pipe"stone`, n.

Defn: A kind of clay slate, carved by the Indians into tobacco pipes.
Cf. Catlinite.

PIPETTE
Pi*pette", n. Etym: [F., dim. of pipe.]

Defn: A small glass tube, often with an enlargement or bulb in the middle, and usually graduated, — used for transferring or delivering measured quantities.