Answer: simplex

AnswerCrossword Clue
SIMPLEXOne-floor apartment
simplexpertaining to or noting a telecommunications system permitting communication in only one direction at a time
simplexa simple word
simplexsimple; consisting of or characterized by a single element
simplexbasic geometric element in a Euclidean space, being a line segment in one dimension, a triangle in two dimensions, a tetrahedron in three dimensions, and so on: used in topology and linear programming
simplexapartment having all the rooms on one floor