Lewis Short
sŭbactĭo (noun F) : subigo.
* Lit., a working through, working up, preparing (rare): harena fluviatica bacillorum subactionibus in tectorio recipit soliditatem,Vitr. 2, 4 fin.: subactiones ciborum,Arn. 3, 107.—*
* Trop., preparation, discipline: subacto mihi ingenio opus est ... subactio autem est usus, auditio, lectio, litterae,Cic. de Or. 2, 30, 131.
Charlton T. Lewis, Charles Short, A Latin Dictionary