Why is the ninth month called September?
c.1400, from Old French spasme, from Latin spasmus "a spasm," from Greek spasmos "a spasm, convulsion," from span "draw up, tear away, contract violently, pull," from PIE *spe- "stretch." Figurative sense of "a sudden convulsion" (of emotion, politics, etc.) is attested from 1817.
1900, from spasm (n.). Related: Spasmed; spasming.
A sudden involuntary contraction of a muscle or group of muscles.
A muscle spasm.