i was reading the FAQ from vampire counts and I found the word rank-and-file a couple of times, can someone explain what this means? to give some examples: Q. Does the Beguile Vampiric Power still work if the Vampire is only in contact with rank-and-file models (non-characters)? If yes, does it mean the player chooses one of the rank-and-file models and so has to separate his rolls to hit and to wound against it? (p83) A. Yes to both questions. Q. Does a unit of rank-and-file Blood Knights suffer any penalty from not nominating a model to accept an enemy challenge? (p46) A. No, the challenge simply does not happen.
Rank and file means "grunts," the guys that you just fill out your unit with. For example, saurus warriors, skink skirmishers, and cold one cavalry models, but not their respective champions or attached characters.
Yep rank and file simply means a unit. A rank is a row of models (eg. the command models are always in the front rank) and a file is the column of the unit, how deep it is. The second FAQ question is a bit more specific to Blood Knights. They have a special rule that any model in the unit can accept challenges (normally only unit champions and characters can).