a luminous discharge caused by the passage of electricity through a gas or vapour; = spark, n.1 6a; also figurative.

A brilliant streak or flash of light produced by a discontinuous discharge of electricity between two conductors at a short or moderate distance…

More fully in electric(al) spark. Also transferred and figurative.

A brush-like electrical discharge of sparks.

= 6a.

a spark produced by the application of a potential difference to two electrical conductors separated by a narrow gap; usually attributive…