I’ve always thought that mold is the fungus, and to mould is to shape. When talking about it with my colleagues yesterday, I was surprised that this isn’t common. Most people use one of the two spellings to refer to both.

Doing a quick search on duckduckgo also confirms that:

• mould is the British spelling referring both meanings.
• mold is the american spelling referring to both meanings.

In my quest to prove them wrong, I was surprised at how wrong I was… until I discovered a few people on the internet who said the same thing:

• https://english.stackexchange.com/a/169920
• https://english.stackexchange.com/a/172089
• https://english.stackexchange.com/a/139605
• https://old.reddit.com/r/confidentlyincorrect/comments/18sx2l0/mold_vs_mould_doubled_down/kfaa6nj/
• https://old.reddit.com/r/confidentlyincorrect/comments/18sx2l0/mold_vs_mould_doubled_down/kfcio12/
• https://old.reddit.com/r/confidentlyincorrect/comments/18sx2l0/mold_vs_mould_doubled_down/kfet3jz/

I’m not looking for what’s correct or incorrect anymore, I just find it very fascinating that there are some people who use the words similarly to me, but the vast majority of others who use it in a different way.

So: what’s the difference between mould and mold according to you?