A snowflake, indicating suitability for freezing.
Also known as: Snowflake symbol, Freezer symbol, Frozen symbol, Freezerproof symbol
A snowflake marks a container as suitable for the freezer. It is unstandardised, and on food packaging the same snowflake means something quite different — how long the food may be kept, not what the container will withstand.
Is not a standardised symbol. No body defines it, its drawing varies between manufacturers, and its presence is the manufacturer's own assurance rather than a certification — so the absence of the mark does not reliably mean the object is unsuitable, and its presence is not a guarantee.
Stated first rather than as a footnote, because it is the most useful thing to know about the mark. Check the manufacturer's own instructions where it matters.
Contexts: Packaging
Indicates that a container will withstand freezing without cracking or becoming brittle.
Contexts: Packaging
Means something else entirely on food packaging, where one, two or three stars indicate how long food may be stored in a freezer compartment of a given temperature — a storage-duration rating rather than a property of the container.
Two unrelated conventions using very similar marks in the same room. The star rating is about the appliance and the food; the snowflake on a tub is about the tub.
Contexts: Packaging
A six-armed star with small branches on each arm, drawn as a stylised ice crystal.
The two temperature extremes a container may be rated for. An item can carry both, one, or neither, and the marks are independent of each other.