spares
n. plural-only B2 Upper Intermediate US //ˈspɛɹz// UK //spˈeəz// spares
n. extra items or parts that you keep in case the ones you are using break or get lost. You often keep them for machines, cars, or household tools.
n. additional components or items kept in reserve to replace those that are damaged, lost, or worn out.
We always keep a few spares in the garage.
The technician brought several spares to the site to ensure the server could be repaired immediately if a part failed.
Maintaining an inventory of critical spares is essential for industrial operations, as the cost of downtime often far exceeds the price of the replacement parts themselves.
Usage
Typically used in the plural to refer to a collection of replacement parts; the singular 'spare' usually functions as an adjective.