Meaning of “siding” - Learner’s Dictionary

siding

noun uk us /ˈsaɪdɪŋ/
RAILWAY [ C ]

a short railway track, connected to a main track, where trains are kept when they are not being used

WALL [ U ] US

material that covers the outside walls of a building, usually in layers

(Definition of “siding” from the Cambridge Learner’s Dictionary © Cambridge University Press)