WordNet sense 1 (electrical conduction through a gas in an applied electric field):

arc, discharge, discharge, electric discharge, electric arc

WordNet sense 2 (Scottish writer of satirical novels (born in 1918)):

Dame Muriel Spark, Muriel Sarah Spark, Muriel Spark

WordNet sense 3 (a momentary flash of light):

flicker, glint

WordNet sense 4 (merriment expressed by a brightness or gleam or animation of countenance):

light, sparkle, twinkle

WordNet sense 5 (put in motion or move to act):

activate, actuate, trigger, trip, set off, spark off, touch off, trigger off