Lewis Short
(verb) : sum-mūto (subm-), āre
* To change, interchange, substitute one thing for another: hanc ὑπαλλαγὴν rhetores, quia quasi summutantur verba pro verbis, μετωνυμίαν grammatici vocant, quod nomina transferuntur, Cic. Or. 27, 93.
Charlton T. Lewis, Charles Short, A Latin Dictionary