The dictionary isn’t a legal framework or international organization. The UN has a convention on genocide:

In the present Convention, genocide means any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such:
(a) Killing members of the group;
(b) Causing serious bodily or mental harm to members of the group;
(c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;
(d) Imposing measures intended to prevent births within the group;
(e) Forcibly transferring children of the group to another group.

Item (c) comes the closest to what Sisko did, but he did it in a way that gave them a chance to get out, so it’s not a perfect match. Forcing conditions for removing a group probably wouldn’t qualify under any of these. That said, it can be a factor in Ethnic Cleansing, but the Maquis aren’t really an ethnic group.