odourless

Everyday

1. Odourless means having no smell at all. tree →
2. (science) An odourless gas or liquid cannot be noticed by your nose. tree →

In the lessons

In science lessons it describes pure water and many gases (oxygen, nitrogen, carbon monoxide). In safety it is a warning: a dangerous gas can be odourless, so you cannot smell it, and alarms are needed. Natural gas at home is given an added smell on purpose so leaks can be noticed. Phrases: «colourless and odourless», «odourless and tasteless».

Examples

• Pure water is colourless and odourless. tree →
• Carbon monoxide is an odourless gas, so homes need alarms. tree →
• Oxygen is odourless and invisible. tree →
• This odourless glue is good for the classroom. tree →
• The paint is odourless, so we can use it indoors. tree →
• Gas companies add a smell to odourless gas so people notice leaks. tree →
• The liquid in the beaker was odourless. tree →
• Is the flower odourless or does it smell sweet? tree →

Note

British spelling odourless, American odorless (same word). «Odour» = smell; «-less» = without. Myth: «if I can't smell it, it's safe» — wrong, some deadly gases are odourless. Do not confuse with «colourless» (no colour).