# QoS

CEFR C2 · Noun

Source: https://englishreference.com/word/qos
Updated: 2026-08-15

## Definition

Stands for Quality of Service. A way to manage internet or network traffic to make sure important data, like a video call, stays smooth and fast.

For teachers: Abbreviation for Quality of Service. The description or measurement of the overall performance of a service, such as a telephony or computer network, particularly with regard to the prioritisation of specific data types to ensure low latency and packet loss.

## Examples

- The router uses QoS to prioritize my video calls over large downloads.
- The network administrator adjusted the QoS settings to ensure that the office's VoIP system remained clear during peak hours.
- Implementing robust QoS protocols is essential for maintaining the integrity of real-time applications, as it allows the system to allocate bandwidth dynamically based on the urgency of the traffic.

## Usage notes

- Often used as a modifier before another noun, such as 'QoS settings' or 'QoS policy'.

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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.