To form a scrum.
A tightly-packed and disorderly crowd of people.
A tightly packed group of reporters surrounding a person, usually a politician, asking for comments about an issue; an opportunity provided for a politician to be approached this way.
In rugby union or rugby league, all the forwards joined together in an organised way.
Hostile shoving between two groups.
In Agile software development (specifically Scrum or related methodologies), a daily meeting in which each developer describes what they have been doing, what they plan to do next, and any impediments to progress.