For superstitious reasons, many buildings number their 13th storey as 14, bypassing 13 entirely.
sto·rey storeys in AM, use story A storey of a building is one of its different levels, which is situated above or below other levels. the upper storeys of the Empire State Building. = floor. a floor or level of a building (story; perhaps because some medieval buildings had paintings on their walls telling stories)
structure consisting of a room or set of rooms comprising a single level of a multilevel building; "what level is the office on?"