One of the four sections made by dividing an area with two perpendicular lines. / (mathematics) One of the four regions of the Cartesian plane bounded by the x-axis and y-axis.

(music) A tuplet of four notes. / A sequence of four elements. / One of a group of four, particularly one of four babies born from the same mother during the same birth.

A polygon with four sides. / An area defended by four fortresses supporting each other.

Having four sides.

A four-footed or four-legged animal. / A mammal ambulating on all fours.

The sound made by a duck.

To make a noise like a duck. / (intransitive) Of a queen bee: to make a high-pitched sound during certain stages of development.

(derogatory) A fraudulent healer, especially a bombastic peddler in worthless treatments, a doctor who makes false diagnoses for monetary benefit, or an untrained or poorly trained doctor who uses fraudulent credentials to attract patients

To practice or commit quackery (fraudulent medicine). / (obsolete) To make vain and loud pretensions.

Falsely presented as having medicinal powers.