All 6 Uses of

encore
in
Arrowsmith

His idol was Professor Edward Edwards, head of the department of chemistry, who was universally known as "Encore."†
Chpt 2 *

encore = an extra or repeated performance

Ordinarily Encore would have suggested, with amiable malice, that Gottlieb was a "crapehanger" who wasted time destroying the theories of other men instead of making new ones of his own.†
Chpt 2

On the campus he met that jovial historian of chemistry, Encore Edwards, and begged, "Say, Professor, tell me, is there any value for a doctor in organic chemistry?"†
Chpt 2

And the great god Sondelius had slain Dean Silva, as Silva had slain Gottlieb, Gottlieb had slain "Encore" Edwards the playful chemist, Edwards had slain Doc Vickerson, and Vickerson had slain the minister's son who had a real trapeze in his barn.†
Chpt 17

Definitions:

(1) (encore)
an extra or repeated performance -- especially of music given in response to audience demand

At the end of a musical performance, an audience will sometimes shout "encore! encore!" to encourage the performance of another piece of music. The term may also refer to a performance by an artist who follows a successful run with a return at a later time.
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

More rarely, "encore" may be used to describe what anyone will do after they have done something well. For example, "The President has been very successful in his first term, but what will he do for an encore?"