Compound noun: Escalator.
Liukuportaat comes from liuku, a noun meaning ”skid” or ”slide,” and portaat, meaning stairs. (Portaat is the plural of porras,which means ”step” or ”stair.”)
A related verb is liukua, meaning ”to slide.”
Rullaportaat (literally ”roller stairs”) is a synonym for liukuportaat.
The other two words on our sign are hissit, plural of hissi, meaning ”elevator” and ovet, plural of ovi meaning ”door.”
(Oh, and Kone – company name in Finland – means ”machine.”)