Ruck has many meanings, including all of the above.
See OED.
ruck- a multitude, a crowd. Found in print from 1581. OED 3b.
ruck- to squat, huddle together. Chaucer, 1386 and earlier. 1582- "That happlye rouke in studente mewes."

One common meaning is in a group- "in one group." OED, 4a.
Wallace, 1922- "Its jockey had given up all attempt at winning and was content to finish with the ruck.
Mark Twain, 1865- "Flowers and general ruck sent to him by every Tom, Dick and Harry from everywhere."
Others-
ruck- to rumple, wrinkle.
ruck- to reprimand, to tell off.
ruck- the jumble in a rucksack.
ruck- to inform on.
ruck- a heap or stack of fuel. Mentioned already, this meaning in print in 1225.
ruck- a particular measure of coal. (no longer used)
ruck- a rick or stack of hay, corn, etc. (Sc. and Northern).
ruck- a rut or a ditch.
ruck- a ridge.
ruck- a flourish of penmanship (Dictionary Laws of Scotland)

etc., etc.