1) a small house with only one storey (bungalow)

2) having, using, only one colour (monochrome)

3) a scene in a play in which only one person speaks; any long talk by one person in a conversation (monologue)

4) of, concerning, a political system with only one political party allowed (totalitarian)

5) having only one possible meaning (unequivocal)

6) being the only one of its kind or standard (unique)