i Register
In some senses, complexus is marked as dated. Watch for register when choosing this word.
noun
A complex, an aggregate of parts
Whenever any of the great complexuses of the nerves, by intestine jars, have entangled themselves, at my approach they range into regular order, and give mutual assistance to each other in a friendly embracing intercourse […]
A large muscle of the back, passing from the spine to the head.