WordNet sense 1 (coil such that current is induced in it by passing a current through the primary coil):

secondary coil, secondary winding

WordNet sense 2 (inferior in rank or status):

inferior, lowly, petty, subaltern, junior-grade, lower-ranking

WordNet sense 3 ((sometimes followed by `to') minor or casual or subordinate in significance or nature or occurring as a chance concomitant or consequence):

incident

WordNet sense 4 (experienced at secondhand):

vicarious

WordNet sense 5 (not as a direct effect or consequence):

indirect

WordNet sense 6 (accompany, concomitant):

collateral

WordNet sense 7 (functioning in a subsidiary or supporting capacity):

auxiliary, subsidiary

WordNet sense 8 (allowing a choice):

alternate, alternate

WordNet sense 9 (of lesser importance or stature or rank):

minor

WordNet sense 10 (lower in rank or importance):

low-level, subordinate