mate a dictionary is the best, however to my knowledge a floor has a wider semantic meaning as oppose to a storey but in the architectural context the meaning is the same
Storey
British
a structure consisting of a room or set of rooms at a single position along a vertical scale.
Floor
1. that part of a room, hallway, or the like, that forms its lower enclosing surface and upon which one walks.
2. a continuous, supporting surface extending horizontally throughout a building, having a number of rooms, apartments, or the like, and constituting one level or stage in the structure; story.
3. a level, supporting surface in any structure: the elevator floor.
4. one of two or more layers of material composing a floor: rough floor; finish floor.
5. a platform or prepared level area for a particular use: a threshing floor.
6. the bottom of any more or less hollow place: the floor of a tunnel.
7. a more or less flat extent of surface: the floor of the ocean.
8. the part of a legislative chamber, meeting room, etc., where the members sit, and from which they speak.
9. the right of one member to speak from such a place in preference to other members: The senator from Alaska has the floor.
10. the area of a floor, as in a factory or retail store, where items are actually made or sold, as opposed to offices, supply areas, etc.: There are only two salesclerks on the floor.
11. the main part of a stock or commodity exchange or the like, as distinguished from the galleries, platform, etc.
12. the bottom, base, or minimum charged, demanded, or paid: The government avoided establishing a price or wage floor.
13. Mining. an underlying stratum, as of ore, usually flat.
14. Nautical.
a. the bottom of a hull.
b. any of a number of deep, transverse framing members at the bottom of a steel or iron hull, generally interrupted by and joined to any vertical keel or keelsons.
c. the lowermost member of a frame in a wooden vessel.
::rk
