- Permitting the flow of air or liquid in one direction only: a non-return valveMore example sentences
- If it is taking in air it means that the non-return valve is leaking and needs to be replaced.
- Self-sealing crashworthy fuel tanks have explosion suppression and non-return valves.
- A non-return flap is usually fitted to prevent cold air coming in.
More definitions of non-returnDefinition of non-return in:
- The US English dictionary