rank-n; 3 Senses

Sense Number 1: A row or line of people.

Commentary: RANK[+group][+structured]

The entrance was guarded by ranks of soldiers.
The ranks of policeman followed the crowd.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: Relative status.

Commentary: RANK[+status]

His salary was determined by his rank and seniority.
The British are very aware of rank.
Colonel is a higher rank than Private.

WordNet 3.0 Sense Numbers: 2, 4

Sense Number 3: The ordinary (or full body of) the members of an organization.

Commentary: RANK[+group]

He rose from the ranks to become a leader.
The rank and file of the order disagree.
They polled their ranks.
He joined the ranks of the unemployed.

WordNet 3.0 Sense Numbers: 3, 5