What is the meaning of 発条?

spring (device made of flexible material)

springiness, bounce, resilience

a springboard, spark, or catalyst leading to some other change

spring (device made of flexible material), specifically the spiral torsion kind commonly used in clockwork that is coiled into a disc shape like a fern fiddlehead

Short for 発条仕掛 (zenmai-jikake, clockwork mechanism, clockwork).

spring (device made of flexible material)

a motivation or catalyst leading to some other change

Source: wiktionary.org