smoke ring

Noun

 * 1) A ring of smoke exhaled by a smoker.
 * A smoke ring persists for a surprisingly long time, illustrating the slow rate at which viscosity dissipates the energy of a vortex.
 * A smoke ring persists for a surprisingly long time, illustrating the slow rate at which viscosity dissipates the energy of a vortex.
 * A smoke ring persists for a surprisingly long time, illustrating the slow rate at which viscosity dissipates the energy of a vortex.
 * A smoke ring persists for a surprisingly long time, illustrating the slow rate at which viscosity dissipates the energy of a vortex.
 * A smoke ring persists for a surprisingly long time, illustrating the slow rate at which viscosity dissipates the energy of a vortex.

Translations

 * Chinese:
 * Mandarin:
 * Finnish: savurengas,
 * French: rond de fumée, ronds de fumée