# reliable

/ɹiˈɫaɪəbəɫ/ (US) · /ɹɪlˈaɪəbəl/ (UK)

Source: https://englishreference.com/word/reliable
Updated: 2026-06-19

## Senses

### 1. trustworthy or dependable

adjective · CEFR B1

someone or something you can trust to behave well or work correctly.

For teachers: consistent in performance or behaviour; able to be trusted to do what is expected.

- My old car is very reliable and has never broken down on a long trip.
- The company is looking for a reliable contractor who can guarantee the project will be finished before the winter holidays.

### 2. data transmission

adjective · CEFR C1 · Technical

a system that makes sure information reaches its destination safely.

For teachers: referring to a protocol that ensures data packets reach their destination or notifies the sender of failure.

- A reliable network connection is essential for making clear video calls.
- TCP is considered a reliable transport protocol because it manages retransmissions to ensure that the data stream remains intact.

### 3. a dependable person or thing

noun · CEFR B2 · Informal

a person or thing that you can always depend on.

For teachers: an entity that is consistently dependable; often used in the phrase 'old reliable'.

- When the new printer broke, we had to use 'old reliable' in the corner.
- Among all the flashy new gadgets, this manual typewriter remains the office reliable whenever the power goes out.

## Examples

- My car is old but it is still very reliable.
- The manager is looking for a reliable assistant who can handle the office while she is traveling.
- While the initial data seemed promising, the researchers needed a more reliable method of collection to ensure the results would hold up under peer review.

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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.