ROOMFUL is a 7 letter word that starts with R.

1. \Room"ful\, a.
   Abounding with room or rooms; roomy. ``A roomful house.''
   [R.] --Donne.
   
   

2. \Room"ful\, n.; pl. {Roomfuls}.
   As much or many as a room will hold; as, a roomful of men.
   --Swift.