All 5 Uses of

convention
in
The Count of Monte Cristo

The actors made their entries and exits unobserved or unthought of; at certain conventional moments, the spectators would suddenly cease their conversation, or rouse themselves from their musings, to listen to some brilliant effort of Moriani's, a well-executed recitative by Coselli, or to join in loud applause at the wonderful powers of La Specchia; but that momentary excitement over, they quickly relapsed into their former state of preoccupation or interesting conversation.†
Chpt 33-34

conventional = normal or typical

The second was the man's conventional abode, or rather sleeping-place; it contained a few poor articles of household furniture—a bed, a table, two chairs, a stone pitcher—and some dry herbs, hung up to the ceiling, which the count recognized as sweet pease, and of which the good man was preserving the seeds; he had labelled them with as much care as if he had been master botanist in the Jardin des Plantes.†
Chpt 61-62

"My child," exclaimed the old lady sharply, "let us hear none of the conventional objections that deter weak minds from preparing for the future.†
Chpt 71-72

He resembles the old Conventionalist of '93, who said to Napoleon, in 1814, 'You bend because your empire is a young stem, weakened by rapid growth.†
Chpt 73-74 *

Monte Cristo bowed without making any answer; he accepted the offer without enthusiasm and without regret, as one of those conventions of society which every gentleman looks upon as a duty.†
Chpt 41-42

Definitions:

(1) (convention as in: teacher's convention)
a large conference or meeting
(2) (convention as in: conventional behavior)
something regarded as normal or typical
(3) (convention as in: The Geneva Convention)
a written international agreement