For me culture is
The way we do things around here.
Fundamental to any group is the idea that each individual member shares a concept about what makes the group a group. To ensure that there is a moral consensus the ethical basis of the group needs to be known and explicit stated; for the group itself, each member, and the others.
This can be either already explicit or can be uncovered through an ethics culture assessment.
Once the moral climate is known then a program ought to be developed to either; ensure that the ethics of the culture remains strong, gets tweaked, or is radically and aggressively put in place.
An ethics program has many features, contains many parts, and ought to include things such as a go to person, a Code of Ethics, an active ethics education plan, a process for raising ethical concerns, and a moral repair process.