"Collectivism" -- preferring to fulfill the needs of the highest percentage of individuals where possible; the practice or principle of giving a group priority over each individual in it. For example, if five occupants share a dwelling, a collectivist perspective would deem it illegitimate for one member to lock out everyone else, burn down the house, or sell it to a third party without obtaining the consent of the other interdependent occupants. Collectivists see such individualistic behaviors as authoritarian, and push instead for everyone having access to what they need, either through sharing or empowering each person to have their own (the latter reflecting a synthesis of collectivist and individualist thinking).
Marxism acts as a sub-category of collectivism in a similar way to how Constitutionalists do not have a monopoly on individualism.
Not all forms of collectivism use majority rule or democracy. The way I practiced anarchy with collectivism in a month-long outdoor band society, we used roughly this process: In the morning we checked in about our projects, and discussed what things the group needed (e.g. firewood, water) and agreed on it using informal consensus. We expressed our preferences and split the tasks into bundles based on what people felt like doing and where they would need to do them, trying to reach a balance so that everyone would feel like they had a meaningful day. Tasks that everyone felt disempowered by but that we felt we needed to do (gather firewood for the winter from across the far marsh) we tried to minimize down to what we actually needed, share the burden of by acting together, and play games while doing it. We informally rotated the tasks for variety, or did them together and told stories to pass the time. We always had our own more individual side projects as well. At dinner we gave an update and checked in on our feelings.
Because everyone had both a desire for autonomy and a desire for fairness, and we planned things creatively as a group, we routinely completed all the necessary tasks with lots of spare personal time: our group subsistence activities took only a few hours a day off and on at most. Individual side projects we could slack off on all we wanted, but that would have wasted our time since we determined those based on our own interest. Usually we had enough variety to prevent boredom, and talking and games always helped. No one forced anyone to do anything the entire time; we all agreed to everything knowingly and voluntarily when we made decisions.
Everything productive, such as tools, we held in common. We “collectivized” tools by keeping them in a common storage area, notifying others when we borrowed them for individual tasks, sharing them as needed, and returning them to common areas when not in use. We didn't use any tools that we could not repair or replace if needed, made sure everyone knew how to use all the tools, and understood that those who broke a tool would repair or replace it.
We didn't have any problems sharing raw materials either; once again, every improvement for an individual contributed to improving the capacity of the group. Since we tried to plan things such that people would only gather materials when they voluntarily decided to and felt fun gathering, we overcame a lot of the ego-attachment and disappointment issues that materialistic people have with sharing. People still had some personal belongings though: no one thought to take someone else's sleeping bag or clothes, though everyone made sure that everyone else had enough of those as it got colder.
So we held almost all of our possessions in common, including food. No locks or fences all month long. Some days we divided the food equally, other days we agreed to just take what we felt we needed. Both worked fine because we lived face-to-face, checked in a lot, and every person had an interest in every other person having their needs met. The more scarce a food item the more we divided it evenly; the more abundant the item the more we took as we desired. We stored the food in a communal structure and in a communal storehouse where everyone had easy access. Sometimes people would feel extra hungry and we'd just get more food. No one hid any food the whole time.
The closest instance we had of the collective overpowering the individual was when storms forced the group to have to move in to a shelter that one person usually slept in alone for our cooking. He moved his stuff over somewhat unhappily, but he would have had a worse time seeing us eat in the hail and snow. We then worked on another winter shelter so as to avoid that issue from recurring.