1. material used to cover the exterior walls of a building
2. a short railroad track connected to the main track

1. present participle of side: supporting or agreeing with someone

Examples

• The house has vinyl siding that needs to be cleaned.
• They installed new cedar siding on the cabin.
• The train pulled onto a siding to let the express pass.
• The freight cars were stored on the siding overnight.
• She’s siding with her brother in the argument.
• The senator is siding with the opposition on this issue.