# sidecar

/sˈaɪdkɑː/ (UK)

Source: https://englishreference.com/word/sidecar
Updated: 2026-08-27

## Senses

### 1. motorcycle attachment

noun · CEFR B2

a small, one-wheeled seat attached to the side of a motorcycle for a passenger.

For teachers: a one-wheeled vehicle or compartment attached to the side of a motorcycle to accommodate a passenger or cargo.

- The old motorcycle had a sidecar so the dog could ride along with his owner.
- Vintage enthusiasts often restore the motorcycle and sidecar as a single unit to maintain the aesthetic of mid-century touring vehicles.

### 3. software pattern

noun · CEFR C2 · Technical

a small program that runs next to a main application to help it work better, like a helper.

For teachers: a design pattern where a secondary process or container runs alongside a primary application to provide supporting features like logging or security.

- The developers added a sidecar to the application to handle all the security checks automatically.
- By deploying a sidecar for service mesh integration, the engineering team decoupled the networking logic from the core business application code.

Usage: Commonly used in the context of microservices and container orchestration like Kubernetes.

## Examples

- The developer added a sidecar to handle the application's security logs.
- In a microservices architecture, a sidecar often manages the communication between different services to ensure reliable data transfer.
- By offloading encryption and authentication to a sidecar proxy, the engineering team simplified the deployment pipeline and ensured consistent security policies across all their cloud-native applications.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.